LGA1366 Video Rendering / Streaming PC Help

[T3Kgamer]

So i decided to try to part together some old LGA 1366 server parts to hopefully make a 8c 16t PC that will be a dedicated machine for editing and rendering videos as well as adding a capture card down the line and using it to livestream what my gaming desktop is doing i already have some parts but I'm having trouble finding a motherboard due to lack of information on the platform
I have a pretty small budget I would like the motherboard to be under ~170USD so ebay listings are very welcome and any other part suggestions are welcome for this build aswell

id prefer this for the motherboard:
- PCIE 16x (8x is fine but i don't want my quadro to be bottlenecked too much)
- ATX form factor
- ability to bclk overclock the processors
- Audio (not neccesary but would be a nice plus)

I don't know if the bclk is possible on server boards if it isn't i might just end up buying a hexacore processor and a enthusiast board or not overclocking and buying a regular server board

Here's the parts i have already
- Corsair 100r
- 2 Xeon E5620
- Quadro FX3800
- 16G ECC DDR3

- Power supply with 2 CPU power connectors
Going to buy
- USB 3.0 Card
- Sound Card (if the board doesn't have one)
- SSD

Edit: am I going to see a good/noticeable improvement in performance overclocking for render times also is my Quadro going to be significantly bottlenecked by pcie 2.0 8x (keep in mind this card is a 2.0 card but if I were to upgrade to a newer card thats 3.0 is the performance going to be crap)

Edited September 12, 2016 by T3Kgamer
Added edit at bottom