for video edition workstation I would probably go with an intel 2p ...
You can get a good workstation board...
a 2p of E5-2690s will perform about the same as a 4p of amd 6168s.
If you want to go amd... go with the latest gen chip so you get AVX support.
If you go 2p you can use Win7 or Win8.... and always go 64bit.
I would go with the Asus Z9PE-D8 WS
2620 is 2ghz and only 6 cores
If you are going to go 6 core go higher clocked.
or 8core @ 2.2
Of note...the all core turbo is generally 4-500mhz on C0 steppings.
Also... to get a C stepping QBxx QAxx are B stepping and no bueno.
If you plan to do lots of VM part of the virtual tech is broken in C1.
@Patriot, you went with AX850 for PSU, was that enough for your 2P system?
Which PSU would I need for 2x E5-2660 64gb of 1600mhz ram, ~4 hdd, and GTX 680. Not sure if the GTX 770 would use less wattage.
A AMD Opteron 6300 series Abu Dhabi / Pile Driver 4P system is faster and cheaper then a Intel Xeon E5 2600 series Sandy bridge 2P system.
So I bought a 2nd e5-2660 off ebay for $385, also another 32gb of memory.
I tried putting in the h80i to the top or sides of my case, they were way too bulky. I'm going to have to get another set of contained liquid coolers, like thin ones. Right now they're sitting on a testbench with crappy aluminium HSF, it's so bad, especially since the heat from cpu1 gets blown to cpu2.