hmm i would go with 2xXeon L5640 (6core) @2,26ghz and SuperMicro X8DTI-F mobo which has enough expansion slots and 2x pcie, also ddr3 memory up to 192gb! It would cost me about 300 euros (cpus and mobo). Interesting build for mining too.. CPU: http://www.ebay.com/itm/Intel-Xeon-L5640-SLBV8-Six-Core-CPU-6x-2-26-GHz-12-MB-Cache-5-86-GT-s-S-1366-/151739455946?hash=item23546059ca:g:5TAAAOxyyFhTc5Fh Mb: http://www.ebay.com/itm/SuperMicro-X8DTI-F-Rev-2-01-Dual-Socket-LGA1366-Motherboard-Server-Board-/371449358965?hash=item567c1b6a75:g:pjMAAOSw0HVWBbHd