building a server
ust a Celeron or i3.
You're building a server but don't need VT-d or TXT? If that's the case, AMD CPUs tend to end up cheaper once you factor in a cheaper motherboard.
If you do need VT-d or TXT, AMD CPUs offer that across their entire range (for current-gen parts anyway) whereas Intel arbitrarily disables these features on certain CPU models
Intel CPUs do have significantly better performance per clock than AMD, but Intel is currently on the 7th-generation of the Core architecture, whereas AMD's Bulldozer is only up to generation 2.
Personally, I need a CPU that runs at 4.2GHz on 4 cores with VT-d support for reasons. I can buy a CPU that has that capability from AMD right now. Intel does not have a product that meets those requirements, or if it does, it is significantly more expensive