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The Impact of Memory Latency Explored

CmdrTaco posted more than 8 years ago | from the stuff-to-read dept.

Hardware 162

EconolineCrush writes "Memory module manufacturers have been pushing high-end DIMMs for a while now, complete with fancy heat spreaders and claims of better performance through lower memory latencies. Lowering memory latencies is a good thing, of course, but low-latency modules typically cost twice as much as standard DIMMs. The Tech Report has explored the performance benefits of low-latency memory modules, and the results are enlightening. They could even save you some money."

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162 comments

first (-1, Offtopic)

Anonymous Coward | more than 8 years ago | (#13932613)

first post

Re:first (-1, Offtopic)

Anonymous Coward | more than 8 years ago | (#13932812)

Now this is a good first post. Quick, simple and to the point with absolutely no trolling. Good job, mate!

FP! (0)

Fordiman (689627) | more than 8 years ago | (#13932617)

The article seems to finish off with, "Don't bother with these unless you want to overclock"

Which makes sense... or not. I'd just buy 533 ram and be done with it.

The real question is: can I buy 533MHz ram and run it slower with lower latencies?

Re:FP! (0)

Anonymous Coward | more than 8 years ago | (#13932779)

I find myself questioning some of the benchmarks. It seems to me that you get an overall system performance boost of anything from 3% to 13% by simply upgrading the RAM. For a $50 price raise this is pretty reasonable.

On a number of the tests there was no performance benefit from the faster RAM but these were typically operations that were bound by the capabilities of another part of the system, Winzip - Harddisk, Games@high resolutions - Graphics card or bus bandwidth. So in these cases the system was waiting around for the other components rather than the memory. It would be interesting to do the same test with a far far lower clocked memory speed wher the rest of the system was still high specked so we could reduce the chance of the bottleneck moving elsewhere. If the graphics card had been a 7800GT and the hard disks had been uber raided I suspect more of the benchmarks would have shown benefits.

However, my take on the whole thing is that for $55 you can increase the performance of your entire system by 3% to 13% by reducing the memory bottleneck. As a proportion of the system cost I actually think that is a good deal.

-Anon

Re:FP! (1)

rrhal (88665) | more than 8 years ago | (#13932827)

Low latency DDR is basically the same as high speed RAM. Its all about how much time it takes for the module to do its thing. IIRC its a little more difficult to hit 2-2-2 than it is to run at high speed so if you want really fast RAM low latency may be your best bet.

Re:FP! (4, Informative)

stinerman (812158) | more than 8 years ago | (#13932866)

The real question is: can I buy 533MHz ram and run it slower with lower latencies?

Yes. I regularly by high speed RAM and downclock it, but run it at lower latency. For instance if I wanted to run my RAM at 400MHz, I'd buy 433/466/500MHz VAL-U-RAM and run it as a stick of semi-premium 400MHz.

Link crashed Firefox (1)

ziggamon2.0 (796017) | more than 8 years ago | (#13932623)

The link seems to crash my Firefox...

A bug to be reported, or what is happening?

Re:Link crashed Firefox (5, Interesting)

Maljin Jolt (746064) | more than 8 years ago | (#13932714)

Beware, one of the banner advertiser on that page (netshelter.net) is trying to buffer overflow with strangely crafted cookie. Hope you do not run your Firefox on Windows...

Re:Link crashed Firefox (1)

failure-man (870605) | more than 8 years ago | (#13932892)

So what is this overflow then, and can it do anything but cause Firefox to segfault on *nix? (You mention Windows. Working exploit there?)

Re:Link crashed Firefox (2, Informative)

isometrick (817436) | more than 8 years ago | (#13932950)

How do you figure? Here's the response:
greg@yak ~ $ wget -U "Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.10) Gecko/20050922 Firefox/1.0.6" --save-headers -O- "http://servedby.netshelter.net/serve.cgi?pid=TECH -REPORT&g=1&m=9&j=1&k=1&id=1016381969816&d=iframe" 2>/dev/null
HTTP/1.1 200 OK
Date: Wed, 02 Nov 2005 16:05:08 GMT
Server: Apache/2.0.46 (Red Hat)
Set-Cookie: ls=1; path=/; domain=.servedby.netshelter.net
Set-Cookie: FCDEFAULT_TECH-REPORT.TECH-REPORT=1|051102160508+1 |cf4bbb50bcb0d4ac; path=/; domain=.servedby.netshelter.net; expires=Wed, 09 Nov 2005 16:05:08 GMT
P3P: CP='NOI NID PSAa PSDa OUR IND COM NAV', policyref="/w3c/p3p.xml"
Expires: Fri, 20 Mar 1998 01:00:00 GMT
Cache-Control: no-cache
Pragma: no-cache
X-Adtrix-Debug: -ac=7 VONCAN728Q405HEITNOV=GT ITTQ405TECHENTHUS728=DD VON728Q405HEISITNOV=DD CRUUKNOV05GEEK728=GT CRUUKNOV05VIPER728=GT VERZTECHENTH728NOV05=DD -ec=1 DEFAULT_TECH-REPORT=#1
Connection: close
Content-Type: text/html; charset=UTF-8
 
<script language='JavaScript' type='text/javascript' src='http://techreport.com/phpads/adx.js'></script >
<script language='JavaScript' type='text/javascript'>
<!--
  if (!document.phpAds_used) document.phpAds_used = ',';
  phpAds_random = new String (Math.random()); phpAds_random = phpAds_random.substring(2,11);
 
  document.write ("<" + "script language='JavaScript' type='text/javascript' src='");
  document.write ("http://techreport.com/phpads/adjs.php?n=" + phpAds_random);
  document.write ("&amp;what=zone:24");
  document.write ("&amp;exclude=" + document.phpAds_used);
  if (document.referrer)
      document.write ("&amp;referer=" + escape(document.referrer));
  document.write ("'><" + "/script>");
//-->
</script><noscript><a href='http://techreport.com/phpads/adclick.php?n=a 1feedc2' target='_blank'><img src='http://techreport.com/phpads/adview.php?what= zone:24&amp;n=a1feedc2' border='0' alt=''></a></noscript>

Re:Link crashed Firefox (4, Funny)

NanoGator (522640) | more than 8 years ago | (#13933029)

"Beware, one of the banner advertiser on that page (netshelter.net) is trying to buffer overflow with strangely crafted cookie. Hope you do not run your Firefox on Windows..."

Just another reason to switch to IE!

Re:Link crashed Firefox (0)

Anonymous Coward | more than 8 years ago | (#13933449)

Or turn on your DEP (Data Execution Protection), like I have on my Athlon 64.

Re:Link crashed Firefox (0)

Anonymous Coward | more than 8 years ago | (#13932968)

Works fine with konqueror

Re:Link crashed Firefox (1)

ChrisMaple (607946) | more than 8 years ago | (#13933371)

I turn off javascript when this happens. This is a nuisance, since a lot of good things require javascript.

Re:Link crashed Firefox (1)

Hillgiant (916436) | more than 8 years ago | (#13933646)

Dynamically turn on and off javascript with prefbar [mozdev.org].

Re:Link crashed Firefox (1)

MikeURL (890801) | more than 8 years ago | (#13933773)

I just installed it and I already love it. In fact, I'm so smitten that there may be a whirlwind romance and a marriage in the near future!

apply this to picking a wife (5, Funny)

0110011001110101 (881374) | more than 8 years ago | (#13932640)

FTFA - Lowering memory latencies is a good thing, of course, but low-latency modules typically cost twice as much as standard DIMMs.

I'd have to say this is right on when applied picking a woman to spend your life with... low-latency memory is a BAD BAD thing, and VERY expensive. My next time around, I'm going with the "CHEAPER", high-latency model that can't immediately recall everything I've ever said while arguing her point... Roses and jewelry can cost you over the long run friends...

Re:apply this to picking a wife (1)

JakusMinimus (49854) | more than 8 years ago | (#13933159)

I'm going with the "CHEAPER", high-latency model that can't immediately recall everything I've ever said while arguing her point...

Fret thee not, for such a beast exists solely in myth!

Re:apply this to picking a wife (1)

Hymer (856453) | more than 8 years ago | (#13933795)

a married geek ??
What have I done wrong ? there are pizza boxes on the floor and AlphaServers in the rack but no wife in my house...

Just stick a few blue LEDs on it... (5, Funny)

phpm0nkey (768038) | more than 8 years ago | (#13932699)

I have no doubt that hardcore PC gamers will shell out the cash for these, regardless of the cost/performance ratio. Once you start paying $500+ for a graphics card, all rational decision making skills are lost.

Re:Just stick a few blue LEDs on it... (0, Redundant)

the_loon (742522) | more than 8 years ago | (#13932802)

phpm0nkey said -- "I have no doubt that hardcore PC gamers will shell out the cash for these, regardless of the cost/performance ratio. Once you start paying $500+ for a graphics card, all rational decision making skills are lost." This is probably the funniest thing I've read all morning...okay, I'll give you all week, its only Wednesday. The sad part is particularly true...heh.

Re:Just stick a few blue LEDs on it... (1)

mindaktiviti (630001) | more than 8 years ago | (#13932820)

One of my friend's friend had this obsession with having the bleedy edge gaming rig and would always upgrade his video card. I think his upgrade cycle compared to mine was something along the lines of 3:1. I'd have a TNT2 Ultra (hand me down), then grabbed a GeForce3Ti200 (second hand from cousin for $100CDN), and just recently I bought a GeForce6600GT when the 7000-series just came out. I'm sure this guy has one of the top of the line ATi cards or something in the $400USD+ range.

Re:Just stick a few blue LEDs on it... (0)

Anonymous Coward | more than 8 years ago | (#13933472)

Thank you for that entirely useless view into your pathetic Canuck life. Have you considered killing yourself to spare the rest of the world? You'd go down in history as a hero.

HAHAHAHA, I'm just kidding, no one will ever remember you or care about you being gone. You stupid fucktard.

Re:Just stick a few blue LEDs on it... (0)

Anonymous Coward | more than 8 years ago | (#13933056)

dude you do realize that Coolermaster sells ram with lighted heatsinks already applied.

they are super special "MATCHED" low latency ram.

I alwasy considered people that buy that marketingspeak a bunch of fools.

Re:Just stick a few blue LEDs on it... (4, Insightful)

timeOday (582209) | more than 8 years ago | (#13933103)

I wouldn't buy a $500 card either but, sheesh, at least they're faster than the cheap ones. This low-latency memory is twice the price for a ~3% boost... I think not.

Re:Just stick a few blue LEDs on it... (3, Insightful)

Iriel (810009) | more than 8 years ago | (#13933128)

This isn't all that funny. I mean, it does make me laugh, but it's far more true than humorous. I constantly get berated by the 'hardcore' gamers for not having the fastest CPU/RAM/GPU/HD when I can still run a lot of games just as well as anyone else. The problem with hardcore gaming equipment is that it has become something like MTV selling you 'cool'.

Guess what? That wicked dual-core CPU actually runs games slower than its single core cousin. That brand-spankin' new video card that cost you $400(or more)? I pay that much once every several years on my video card. The difference is that I don't care if I squeeze out my maximum frames per second because most people can't even detect the difference if the game didn't have an option to show the number in the corner of the screen like some veritable rating of thier manhood (sorry for my gender bias on that). And that super ultra OHMYFUCKINGGODITMAKESMYEXPLODEITSSOFAST low-latency RAM is giving you a performance boost of 2% of what I've got now.

I find it educational to read these reports so I can make educated purchasing choices. For that, I'm quite grateful. However, I find it kind of sad that the parent post is unsettlingly accurate in that the 'hardcore pc gamers' will shove this to the side for the ATI SXL 10G Super Elite XTRME Pro card next week. Witness what happens when PC gaming meets MTV-esque marketing.

Re:Just stick a few blue LEDs on it... (1)

DrSkwid (118965) | more than 8 years ago | (#13933248)

> when I can still run a lot of games just as well as anyone else.

is that right ? What FPS are you getting in Quake 4 at 1280x1024x32 with tri-linear and models/textures set to HIGH ?

Re:Just stick a few blue LEDs on it... (3, Insightful)

Iriel (810009) | more than 8 years ago | (#13933307)

You seemed to have missed the point that 'a lot of games' does not mean 'all games', 'any games', or any derivative thereof. And honestly, the point of my post is that I'm willing to sacrifice some detail and put my settings at 75-80% instead of maxed-out if it'll save me from spending close to a thousand dollars a year in upgrades.

Re:Just stick a few blue LEDs on it... (0)

Anonymous Coward | more than 8 years ago | (#13933322)

85, 95 when I stick my peepee into the Zip drive slut. I mean "slot."

Re:Just stick a few blue LEDs on it... (0)

Anonymous Coward | more than 8 years ago | (#13933346)

Hello, McFly. Your super-duper graphics are nothing more than a high-res skin on a game that's going to play exactly the same regardless of what machine it's on (provided the machine meets reasonable specs, of course). I mean, it's not like the go-fast stripes and Kanji stickers on your '89 Civic suddenly turn it into a Ferrari.

Re:Just stick a few blue LEDs on it... (1)

DrSkwid (118965) | more than 8 years ago | (#13933603)

and you think < $10 a week is too much to pay for that ?

FPS makes a difference to playability, anyone that says otherwise has dull senses.

Re:Just stick a few blue LEDs on it... (1)

(A)*(B)!0_- (888552) | more than 8 years ago | (#13933418)

"I constantly get berated by the 'hardcore' gamers for not having the fastest CPU/RAM/GPU/HD when I can still run a lot of games just as well as anyone else."
Why are you associating with such people?

"However, I find it kind of sad that the parent post is unsettlingly accurate in that the 'hardcore pc gamers' will shove this to the side for the ATI SXL 10G Super Elite XTRME Pro card next week. Witness what happens when PC gaming meets MTV-esque marketing."
Sad? Who cares? Let people spend their money the way they want to. If they insult you because you don't spend your money on high-end video cards, don't associate with them. But just as you don't like being insulted for not spending your money that way, don't call people "sad" who do. Just let people live.

And I have never spent more than $200 on a video card.

Re:Just stick a few blue LEDs on it... (0)

Anonymous Coward | more than 8 years ago | (#13933728)

Hey Cheer up Emo Kid!

I don't know what reviews you been reading but every review I have see thus far shows an AMD 64 X2 4800+ (2.4 GHz Toledo) beats an AMD 64 4000+ (2.4 GHz Clawhammer) in just about every benchmark I have seen?

Re:Just stick a few blue LEDs on it... (4, Interesting)

HavokDevNull (99801) | more than 8 years ago | (#13933939)

Have to agree with AC on the cpu issue, taken from the http://techreport.com/reviews/2005q2/athlon64-x2/i ndex.x?pg=16 [techreport.com]

Conclusions
Let's start by talking about the Athlon 64 X2 4200+. This CPU generally offers better performance than its direct competitor from Intel, the Pentium D 840. Most notably, the X2 4200+ doesn't share the Pentium D's relatively weak performance in single-threaded tasks like our 3D gaming benchmarks. The Athlon 64 X2 4200+ also consumes less power, at the system level, than the Pentium D 840--just a little bit at idle (even without Cool'n'Quiet) but over 100W under load. That's a very potent combo, all told.

In fact, the X2 4200+ frequently outperforms the Pentium Extreme Edition 840, which costs nearly twice as much. Thanks to its dual-core config, the X2 4200+ also embarrasses some expensive single-core processors, like the Athlon 64 FX-55 and the Pentium 4 Extreme Edition 3.73GHz. Personally, I don't think there's any reason to pay any more for a CPU than the $531 that AMD will be asking for the Athlon 64 X2 4200+.

If you must pay more for some reason, the Athlon 64 X2 4800+ will give you the best all-around performance we've ever seen from a "single" CPU. The X2 4800+ beats out the Pentium Extreme Edition 840 virtually across the board, even in tests that use four threads to take best advantage of the Extreme Edition 840's Hyper-Threading capabilities. The difference becomes even more pronounced in single-threaded applications, including games, where the Pentium XE 840 is near the bottom of the pack and the X2 4800+ is constantly near the top. The X2 4800+ also consumes considerably less power, both at idle and under load.

The X2 4800+ gives up 200MHz to its fastest single-core competitor, the Athlon 64 FX-55, but gains most of the performance back in single-threaded apps thanks to AMD's latest round of core enhancements, included in the X2 chips. The X2 4800+ also matches the Opteron 152 in many cases thanks to Socket 939's faster memory subsystem. Remarkably, our test system consumes the same amount of power under load with an X2 4800+ in its socket as it does with an Athlon 64 FX-55, even though the X2 is running two rendering threads and doing nearly twice the work. Amazing.

There's not much to complain about here, but that won't stop me from trying. I would like to see AMD extend the X2 line down two more notches by offering a couple of Athlon 64 X2 variants at 2GHz clock speeds and lower prices. I realize that by asking for this, I may sound like a bit of a freeloader or something, but hey--Intel's doing it. No, the performance picture for Intel's dual-core chips isn't quite so rosy, but the lower-end Pentium D models will make the sometimes-substantial benefits of dual-core CPU technology more widely accessible. If AMD doesn't follow suit, lots of folks will be forced to choose between one fast AMD core or two relatively slower Intel cores. I'm not so sure I won't end up recommending the latter more often than the former.

Beyond that, the giant question looming over the Athlon 64 X2 is about availability, as in, "When can I get one?" Let's hope the answer is sooner rather than later, because these things are sweet.

Re:Just stick a few blue LEDs on it... (2, Informative)

Wonko (15033) | more than 8 years ago | (#13933872)

Guess what? That wicked dual-core CPU actually runs games slower than its single core cousin.

Is this actually a true statement? I can't do any current testing since I don't have a reasonable 3D card in my machine, but I remember testing Quake 3 on my old dual Celeron machine with a TNT2 card. top showed Quake was using 95% or more of one CPU, and the X server was using 30% or more of the other CPU.

I don't expect the numbers to be the same today, but shouldn't there be at least some slight increase in speed if the GUI is running in a separate process? I am not saying that the increase would justify the price, but I haven't run a single CPU desktop in something like six years. I am not about to start now :).

Re:Just stick a few blue LEDs on it... (3, Interesting)

vmcto (833771) | more than 8 years ago | (#13933594)

Hey don't knock gamers that spend tons of money on computer gear.

It's thanks to them that the rest of us can get normal gear at such reasonable prices...

No, that's why prices are high. (0)

Anonymous Coward | more than 8 years ago | (#13933750)

In an interview nvidia's chief blatantly said such. He sees no end in sight to how much they can gouge. The tools who spend tons of money for pocket lining havn't balked at the price hikes so far so nvidia et al intend to keep hiking.

Anandtech did this months ago (4, Informative)

Anonymous Coward | more than 8 years ago | (#13932719)

http://anandtech.com/memory/showdoc.aspx?i=2392 [anandtech.com]

You'll basically find that the performance of value memory is very on par with the high end stuff. You basically pay for the ability to overclock on a more consistent basis.

Can't Read the Article (1, Interesting)

Ed Almos (584864) | more than 8 years ago | (#13932728)

I'm running Firefox 1.0.7 under Ubuntu. When I click on the link firefox exits, am I the only one having this problem?

Ed Almos

Re:Can't Read the Article (1)

0110011001110101 (881374) | more than 8 years ago | (#13932785)

I'd have to say no...

http://hardware.slashdot.org/comments.pl?sid=16710 1&cid=13932623 [slashdot.org]

considering just a handful of posts above you, another user complained of the same thing, and yet another user provided a useful reason why:

Beware, one of the banner advertiser on that page (netshelter.net) is trying to buffer overflow with strangely crafted cookie. Hope you do not run your Firefox on Windows...

Re:Can't Read the Article (1)

trparky (846769) | more than 8 years ago | (#13933559)

It don't crash on my Windows XP machine. Then again, I have damn good blacklist loaded into my FireFox AdBlock extension. It ends up blocking close to 98% of all Internet ads. Also, having DEP (Data Execution Protection) enabled helps too.

Re:Can't Read the Article (0)

Anonymous Coward | more than 8 years ago | (#13932803)

The link crashes Mozilla 1.7 also.

Re:Can't Read the Article (1)

Progressive4Peace (905985) | more than 8 years ago | (#13933181)

I'm running Firefox 1.07 on Ubuntu as well - having no problems. I also have adblock running, however, and I heard that site contains a malicious cookie on it so I might not be seeing it because of that.

Re:Can't Read the Article (1)

1336 (898588) | more than 8 years ago | (#13933404)

Same here; details for comparison:

OS: Ubuntu 5.10
Browser: Firefox 1.0.7-0ubuntu20
Extension: Adblock 0.5.2.039
Filter: Filterset.G [nyud.net] 2005-10-31a

Re:Can't Read the Article (4, Funny)

DrWhizBang (5333) | more than 8 years ago | (#13933202)

Sounds like a memory timing issue - you should upgrade to some OCZ low-latency RAM!

(I'm sorry, that's not helpful at all, is it?)

Insightful article (2, Informative)

mindaktiviti (630001) | more than 8 years ago | (#13932772)

Although I didn't read all the text (about 50% of it), the benchmarks were what I was interested in, as well as the conclusion. So to sum it up:

2-2-2-5 timings at 400MHz t1 memory is the fastest but costs twice as much and the performance gains are almost non-existant except in lower resolution games (i.e. 800x600 you may see an increase in 20 fps, which I think is a lot!), and of course the cost of the ram in this case would not be justified because putting that extra money into a better video card would be the better thing to do.

Only if you're an overclocker is this worth it, at least from their benchmarking and perspective, which I'll accept.

Oh yes, and that website also crashed my Firefox.

Re:Insightful article (0)

Anonymous Coward | more than 8 years ago | (#13932863)

800x600? Won't you already be getting >100 FPS in most games anyway?

Re:Insightful article (2, Insightful)

mindaktiviti (630001) | more than 8 years ago | (#13932926)

800x600? Won't you already be getting >100 FPS in most games anyway?

Perhaps, that particular benchmark was for Far Cry at 800x600 w/ medium settings, and the lowest fps was around 168, and the highest was 188, so a 20fps difference.

They were using this video card: NVIDIA GeForce 6800 GT with ForceWare 77.77 drivers

However if you look at the opportunity cost of buying this ram because you have a bad video card and play at those resolutions, then it would still be more worth it to just get a better video card. Even if you want to upgrade your ram, it would be wiser to just save that extra money to put into a 6600GT or something.

It would have been interesting if they did the test with an older video card as well, like a GeForce3 series.

Re:Insightful article (0)

Anonymous Coward | more than 8 years ago | (#13933045)

Once again, a worthless benchmark on /.

Why not do a benchmark that actually tests memory bandwidth and throughput - not the video card, the video card bus, or any other subsystem to an extent that the memory system is not the bottleneck in the test.

A good rule of thumb is that if the benchmark post contains *any* type of MS Office software benchmark, you can discount the findings as worthless, and the creators of the test as idiots if they try to pass it off as meaningful.

Then again, I guess the only real use of a windows box these days is gaming...

If you can afford a cup of coffee a day... (1)

MLopat (848735) | more than 8 years ago | (#13932833)

By the same logic as those cheesy insurance commercials, where you can afford the policy if you can afford a cup of coffee a day, if you can afford to spend 5 minutes reading slashdot each day, then you can afford not to drop twice the amount of money on ram for the 2% time savings it offers in most programs.

Re:If you can afford a cup of coffee a day... (4, Funny)

merdaccia (695940) | more than 8 years ago | (#13933405)

Your analogy does not hold. Slashdot is a high latency site. By the time I've read a few comments, I've usually forgotten what the story was about.

Wait, why am I posting this comment again?

Conclusions (0)

Anonymous Coward | more than 8 years ago | (#13932848)

Although tighter memory timings and a 1T command rate can certainly improve the performance of the Athlon 64's memory subsystem, that improvement doesn't always translate to better application performance. In fact, with the exception of the Sphinx speech recognition engine, moving to tighter memory timings or a more aggressive command rate generally didn't improve performance by more than a few percentage points, if at all, in our tests. Lower latencies only improved WorldBench's overall score by a single point, and performance gains in games were generally limited to lower resolutions and detail levels.

At the end of the day, the appeal of low-latency memory modules may be limited to overclockers and enthusiasts intent on squeezing every last drop of performance from a system. More pedestrian "value" memory should be plenty fast enough for everyone else, especially since you can practically afford twice as much.

But surely flashing LEDS make it go faster! (3, Funny)

Cr0w T. Trollbot (848674) | more than 8 years ago | (#13932865)

After all, that's the main feature of Crucial Ballistix Tracer Memory [crucial.com]. I'm sure those LEDS must be worth at least 10 fps in Doom 3...

Crow T. Trollbot

My LEDs are blinkier than yours! (1)

cerebis (560975) | more than 8 years ago | (#13934085)

I find Corsair Xpert to be the funniest of the Gam3r memory products.

Google Images [google.com.au]
PDF from company [corsairmemory.com]

Note, due to their width, you can only put in one per bank. :)

Ostentation doesn't work so well when inside an opaque case.

Ask a builder (2, Insightful)

Dragoon412 (648209) | more than 8 years ago | (#13932901)

Seriously, this has been known very well amongst the gaming PC builder crowd for a long time. Most of them, anyways; there's unfortunately still that level at which people know enough to put the PC together, but don't know enough to tell you what any of the numbers mean.

The difference between, say, Corsair Value Select memory, and Corsair 1337 Ultra X2000 - the memory equipped with LCDs, heat spreaders, and a spoiler with metal-flake yellow paint that add at least 10 horsepower - is going to be absolutely unnoticeable in the real world. Even benchmark scores will show little to no improvement.

Ricer RAM - you know, the PC equivalent of this crap [hsubaru.com] - is for overclocking. If you're not planning on overclocking it, you're paying too damned much.

Re:Ask a builder (1)

Evil_Timmy (658737) | more than 8 years ago | (#13933010)

Compared to the people who are willing to cool their CPUs with liquid nitrogen for five minutes and risk cracking the core, hyper-accelerated chip creep, shorting from rapid condensation, and a number of other potential issues, just to turn out a few extra 3dmarks (thankfully, Futuremark's killed off that crowd with ridiculous releases time and time again) or gain a few more MHz than the next hardcore overclocker down the line...paying near double the price for a 2-5% increase in performance (on a good day) seems downright reasonable. In my case, I've only bought Corsair for their high-performance EEC memory for a critical server; hardcore memory at average (rated) speeds is rock-solid, and their tech support department and RMA policies are the best you can get without a $10k+ support contract.

Re:Ask a builder (3, Insightful)

theantipop (803016) | more than 8 years ago | (#13933102)

What most people don't realize is that the only way to improve your performance at the top end of the performance spectrum is through a combination of small tweaks such as this. Sure spending twice the money for 103% of the performance sounds dumb, but when you combine that with small tweaks to your processor, graphics card and a 10,000rpm hard drive they add up.

These products are not for people who want to achieve a useable level of performance and as such are not marketed at those crowds. They are for people who have already fast equipment but want more. I won't say this is a good or bad thing as it is simply a hobby for most of these people. Just like import tuners: they may drive funny-looking cars, but it's their choice of hobby.

Not to harp on the obvious (1, Interesting)

Anonymous Coward | more than 8 years ago | (#13932919)

But they're doing this on an AMD-64 platform...

The underestimated impact of latency. (1, Insightful)

G4from128k (686170) | more than 8 years ago | (#13932931)

These tests underestimate the performance impact of latency because they are conducted using software optimized over the years for the high-latency realities of current-day memory architectures. CPU clock speeds have been outstripping RAM clock speeds for about 15 years. Software developers have spent years optimizing their code to mitigate the impacts of latency.

In the short-run, these tests help a person decide whether to buy low-latency RAM. But they provide little long-term insight into how much faster the entire system could be if low-latency were the norm and compilers, libraries, operating systems, and applications were re-optimized for low-latency, not high-latency, architectures.

You really think so? (1)

Gothmolly (148874) | more than 8 years ago | (#13933249)

"Software developers have spent years optimizing their code to mitigate the impacts of latency."

Really? MS hand-tunes the ASM code generated when they do a build of winword.exe ? Maybe thats why OO.o is so slow?

If I sound sarcastic, I suppose I am. With a few exceptions, almost every coder I've worked with in multiple jobs, has been of the 'throw CPU cycles' at the problem. I can count on one hand those who actually design for a HW architecture, since most of the coders these days are VBScript and Java kiddies.

Re:The underestimated impact of latency. (5, Interesting)

Zathrus (232140) | more than 8 years ago | (#13933256)

Sorry, I call BS on your entire post. The difference in latencies here is miniscule -- it's not like we're talking about having the CPU wait 2 clock cycles vs 30 clock cycles. It's closer to 13 vs 25 (not exact, but the magnitude of difference is close). That just doesn't matter that much -- the reality is that if you have a cache miss then you're looking at 20-30 cycles (or, more likely, 40-60 cycles) of stall while you fetch the data from main memory.

The kind of changes you're talking about require vastly faster memory. Not the kind of latency differences being discussed here at all. Both of these are "high latency" compared to what would be needed for your theoretical redesign of the entire software stack. And even then, you just become utterly and completely screwed if you have to hit virtual memory, possibly more so than you are now because you've re-orchestrated everything around the idea that latency is a non issue.

Oh, and latency is getting worse, not better, and has been for a long, long time. CPU speeds long ago outstripped the speeds of our fastest memory (well, fastest while still not costing absurd amounts of money...), and the newer memory formats (DDR, DDR2, DDR3, RDRAM, etc) have higher latencies in exchange for greater bandwidth.

Re:The underestimated impact of latency. (2, Informative)

twiddlingbits (707452) | more than 8 years ago | (#13933313)

The software knows nothing about memory latency, the software only knows it needs to move a block of data from point A to point B. That Java/C/C++ Move_Memory function translates at the lowest level to machine code instructions which are implemented in the logic of the silicon. The coder or the compiler may optimize the ORDER of execution of the instructions, or use different instructions (such as BlockMoves) to speed things up, but the basic underlying machine instructions execute the same way every time (either they hit the cache and load from there, or it misses and a memory fetch is executed across the memory bus). On-chip caches were a design to minimize memory fetch and it's associated latency. On-chip caches are small and fast and are a different design than the external memory.

What you would want is to eliminate the wait states from CPU to RAM (or get more cache hits) and that is NOT something a compiler or OS can do for you, that is done in the algorithms that run the CPU. You can change that to some extent in the BIOS settings, to tell the CPU that memory wait states are zero, or the clock is higher but IIRC the CPU and Memory and Bus Controller have to agree on all this setting and must be able to implement its' timing. Overclocking the CPU won't fix this when the Bus and Memory can't run any faster.

What does this mean? (2, Interesting)

Flying pig (925874) | more than 8 years ago | (#13933451)

All memory has an access time, and the further you get from the CPU the longer it is going to be. CPU registers have the shortest access time, with (nowadays) subnanosecond access. L1 cache comes next, then L2, then external RAM, then HDD, and finally the slow backing store represented nowadays by CD and DVD. This heirarchical memory architecture changes with time mostly in that the caches grow bigger, so the 640K of RAM from DOS days now fits into the cache of each processor in a pentium-D with room to spare, and a Pentium-M could in theory run DOS with extended and expanded memory without needing any external RAM at all. (I'd almost like to try that.)

So talking about optimisation for low-latency RAM is, I suspect, nonsense. What we are surely seeing here is that the actual limitation on memory bandwidth is somewhere else - in the memory controller,in the cache controller, in the CPU fetch rate, in the rate at which stuff is being fetched from hard disk, in bus contention. Overclocking - speeding up memory controllers and buses - will have an effect. Reducing the number of wait states on the memory bus will not have much effect on performance if the total number of active memory cycles in a given period is largely unchanged.

If you had a need for real speed in an application which was not dependent on the graphics subsystem or access to network and HDD, I am sure you could get much more performance out of low-wait state RAM, but you would do it by HARDWARE design, not by software optimisation.

As a simple example from the dim and distant past when I was building hardware, TI used to have a microcontroller called the TMS9995 which ran at, for the day, a hefty 12MHz. With the slow DRAM of the time, it always needed a wait state and this meant that it could manage, as I recall, two memory accesses per microsecond. With static RAM, it could manage 3. The 9995 actually stored its working registers in external memory and so this meant a real world speedup of nearly 30%. The 8088, on the other hand, kept its working registers on-chip and had a limited instruction pipeline. As a result, the equivalent speedup was nothing like 30%. This was due to hardware differences not software differences.

In fact, the applications which really test out the memory subsystem are not games - they are databases and webservers, which hardly use the graphics system at all. And in these cases, for low end systems, the big beast in the equation is cache. It's quite astonishing how a Pentium-M can churn through a badly designed join while a low end AMD 64 struggles, simply because one has 2Mbytes of cache and the other has only 512K. As a result, for ordinary technical laptop and desktop work, I now specify Pentium-M, the AMD 64 with 1Mbyte cache, or pentium-D with 1Mbyte per core. You know it makes sense.(And now everyone can explain why I'm wrong, in my turn)

Re:The underestimated impact of latency. (1)

ChrisMaple (607946) | more than 8 years ago | (#13933620)

RAM not on the CPU chip has been and will continue to be a burden on performance. Low latency RAM will reduce this trend but not reverse it. The physical distance between the CPU and RAM adds to latency due to speed-of-light delays, and it's hard to avoid that.

Re:The underestimated impact of latency. (0)

Anonymous Coward | more than 8 years ago | (#13934064)

To emphasize on this point: In the world of the 8-bit home computers of the 80's, just about any algorithm more complicated than an addition could be made blazingly fast by using look-up tables and jump tables -- by sacrificing memory for processing speed. Memory at the time was scarce, but so was processing speed, and finding the right balance often involved 10 to 50 % of your memory in look-up tables.

Today, all this has changed: to avoid cache misses, you try to avoid using memory as much as possible, jump tables are a disaster because they cannot be handled by the CPU branch predictor, and it can make sense to repeat comparatively complex computations simply because the CPU is so fast and keeping old results in memory is so slow.

What about cache? (3, Interesting)

antifoidulus (807088) | more than 8 years ago | (#13932947)

Improvements in memory speed crawl compared to improvements in CPU speed, however larger caches can mitigate this problem to a certain extent, so why is it that growth in cache size continues to crawl? The Apple G5 updates FINALLY gave us 1mb l2 cache per core(and of course the industry standard 64k L1 cache per core) and whil the Intel/AMD world is slightly better in this regard, it's not by much. So why is it so hard to increase cache size?(of course you will need good cache allocation/replacement policies to go with them)? I'm not trolling, I honestly want to know. I realize that the people that design these chips are a lot smarter than I, but so far I haven't really seen a good reason why they don't increase cache size.
Also, outside of the HPC world, it seems very few programmers optimize their cache usage. Are there any tools(open source or otherwise) that can actually help you locate/fix inefficient uses of cache?

Re:What about cache? (1)

tradiuz (926664) | more than 8 years ago | (#13932999)

Why only a 64k L1 and 1mb L2? Why not a 1mb L1 and 4mb L2?

Re:What about cache? (1)

toleraen (831634) | more than 8 years ago | (#13934038)

I don't recall for sure, but i seem to remember it being about fitting it onto the chip. Since its L1, it needs to be accessed incredibly quickly, so it needs to reside near the gates/pipelines/however you call it. Adding more registers to hold the data would take more physical space, would need to be seperated further, and would cause more latency in retrieving data. That's just my vague recollection from a lesson about the 80386...so it could be way off heh.

Re:What about cache? (1)

prefect42 (141309) | more than 8 years ago | (#13933026)

They've moved towards on die cache, and that makes it expensive. A typical CPU uses a hell of a lot of chip area for cache already. Why do you think P4 EE costs so much?

Re:What about cache? (1)

gnasher719 (869701) | more than 8 years ago | (#13933038)

>> The Apple G5 updates FINALLY gave us 1mb l2 cache per core(and of course the industry standard 64k L1 cache per core) and whil the Intel/AMD world is slightly better in this regard, it's not by much.

Remind me again, how much L1 cache exactly does a Pentium 4 have? Wasn't it something like 8KB fast cache on the older ones and 16KB at half the speed on the newer ones?

Re:What about cache? (0)

Anonymous Coward | more than 8 years ago | (#13933066)

So why is it so hard to increase cache size?

Because L2 cache resides on-die. Take a look at CPU's with 1 or 2MB of L2 cache. Over half the die is cache. More cache makes chips bigger, hotter, and more expensive.

L3 cache, which is usually not on-die, is usually a lot bigger. I recall IBM p-series of servers support something like upto 128MB of L3 cache per MCM (multi-chip module of 4 CPUs).

Re:What about cache? (1)

sznupi (719324) | more than 8 years ago | (#13933090)

Obvious reason - much more expensive (you can't get as good yields at manufacturing fab)

Re:What about cache? (2, Informative)

harrkev (623093) | more than 8 years ago | (#13933092)

For one simple reason -- die size. Cache eats up a lot of real estate. A 1MB (B as in byte) is 8 million bits. If the cache uses DRAM-style cells, that is at least 8 million transistors. If the cache is more like SRAM, then you can count on a lot more This increases the size of the die, which decreases both the number of chips per wafer, and also increases the percentage of defective dies.

So, the bottom line is that cache is the most expensive type of memory in a computer. Some methods have been made to get around this -- like the Intel "Slot-1" architecture where the L2 cache was on a separate chip. But this idea faded into the museum of bad ideas.

Re:What about cache? (2, Informative)

timeOday (582209) | more than 8 years ago | (#13933145)

Because you get diminishing returns for more and more cache. At some point it's better to use all those transistors as a second core instead.

Re:What about cache? (0)

Anonymous Coward | more than 8 years ago | (#13933897)

"Because you get diminishing returns for more and more cache. At some point it's better to use all those transistors as a second core instead."

Pretty much, and the reason why you get diminishing returns is due to program locality. If you take a program (sequence of instructions), you'll notice that the program tends to stay in one area for a long time before moving to a completely different area. This is true for most programs except some programs that are particularly branch-intensive. Modern compilers now offer algorithms to gain more locality in your code without you explicitely programming for it. The OS and hardware also have techniques in place for optimizing reducing cache misses. At some point you're going to have fewer and fewer cache misses that increasing the cache size won't help much if at all.

Lots of research has been poured into creating techniques or algorithms for dealing with slow memory and the result is the memory hierarchy. At the bottom you have your hard disk and at the top you have CPU registers. All of the technologies in both OS, compilers, and hardware all account for dealing with this architecture these days.

It makes sense though: in the ideal situation you want to have a massive amount of cheap memory, not expensive memory.

Save money? (1)

PhilHibbs (4537) | more than 8 years ago | (#13932983)

They could even save you some money
How so? The article indicates that the benefits are marginal. How can this RAM save money?

Re:Save money? (1)

BushCheney08 (917605) | more than 8 years ago | (#13933014)

The submitter is saying that this Tech Report article could save you money, in that if you read it, you will be informed that low latency memory isn't necessarily worth the extra cost. C'mon, rub those brain cells together...

Re:Save money? (0)

Anonymous Coward | more than 8 years ago | (#13933053)

How so? The article indicates that the benefits are marginal. How can this RAM save money?

Hmmmm...let me think, let me think....Oh, maybe by NOT BUYING IT!

Did that breeze over your head feel nice and refreshing?

Re:Save money? (1)

PhilHibbs (4537) | more than 8 years ago | (#13933493)

Great, I'll not buy a hundred then. Wow! I just saved a ton of cash!

Re:Save money? (0)

Anonymous Coward | more than 8 years ago | (#13933537)

Great, I'll not buy a hundred then. Wow! I just saved a ton of cash!

You must be pretty smart, huh? I've got a bridge you can not buy and you'll save even more money! You'll be rich! Then you'll be able to afford that expensive RAM to impress chicks!

Importants of clock speeds (1)

springbox (853816) | more than 8 years ago | (#13933062)

If people are concerned about the speed of their memory, then having fast DDR SDRAM running on an equally fast FSB is what really makes a difference. This is especially true on P4 Celeron based systems where the L2 cache isn't huge and cache misses are common. While memory latency is important to consider, it isn't critical that your modules have the absolute fastest timings ever. I think that the importance of the other components that connect to your memory like the FSB are underestimated. You can have fast memory, but still have it traveling over a slow or congested bus.

The real issue ... (4, Insightful)

TheCrig (3178) | more than 8 years ago | (#13933083)

... Is not memory performance as such, but system performance. If a 5 percent increase in system performance increases the cost of your system by 10 percent, you have to want it pretty badly or be on the edge of required performance or just be in a schoolyard comparison. But if it's reversed, and a 10 percent increase in system performance can be had for a 5 percent increase in system price, then if you can afford the 5 percent (say $100 for a $2000 system), go for it.

well Duh? (1)

thebdj (768618) | more than 8 years ago | (#13933098)

I mean did anyone seriously think that these memory latencies were going to have a great impact on anything that the most common users care about? I mean game performance is barely touched at all, which is another Duh! I think their conclusion is probably right, the people buying these things are the idiots who want to post how they have the ultimate system with great RAM and everything, where they probably only could afford 1 GB of their stuff, my performance and load times are better because I could afford the 2 GB of my 'slower' RAM.

Geeze, must be a slow week for hardware...

server db/compile performance? (0)

Anonymous Coward | more than 8 years ago | (#13933283)

Anyone have any benchmarks on how much faster a compile, DB or app server gets with better memory like this?

Memory Timing Analysis (1)

DrkShadow (72055) | more than 8 years ago | (#13933664)

I remember an article published on Slashdot a year or two (or three or four?) ago about a memory timing analysis. A copy is available here:

http://www.techwarelabs.com/reviews/memory/memory_ timings/index_3.shtml [techwarelabs.com]

The net impact of the CAS latency: 0-0.002%. Almost _nothing_.

The great thing about this article is that it goes into just about every aspect available in the bios, giving you a good idea of what _does_ work (a brief scan-through reveals clock speed as the primary contributor, dram command rate and Active to Command (Trcd?)).

Happy reading.

-DrkShadow
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