This is the Year of ARM. Check out Marvell’s latest CPU. 1.6gHz X4 with 64bit ECC RAM capability. Servery for sure. This would make a fine thick client too if you don’t do too much floating point maths. It uses only 10 watts for 16600 DMIPS! x86-64, Watch Out!
The thing to watch for is multiples of these in a box so each CPU has only to handle a few processes to give huge throughput.