For SQL Server usage, modern Intel processors perform much better than modern AMD processors. You would want to be looking at something like an HP DL380p Gen 8, with Xeon E5-2600 series processors, which will give you much better single-threaded performance than anything from AMD. SQL Server 2012 Standard Edition has a physical processor core limit of 16 cores (or four sockets), whichever is lower.

It also has a memory limit of 64GB for the database engine. You should consider getting more than 32GB of RAM (since DDR3 ECC RAM is very, very affordable). I would actually get slightly more than 64GB of RAM (such as 72GB or 96GB) so you can set your Max Server Memory at 64000. Having lots of RAM will relieve pressure on your I/O subsystem, and RAM is cheaper and faster than any I/O subsystem.