6970 Crossfire Advice


Apr 24, 2011
I'm thinking about possibly getting a second 6970 for my rig, but I have some concerns.

Firstly, is it ultimately worth it?

Second, and sort of tied into the first question, will I experience a significant boost with a PCI-E x16/x8 slot combination as opposed to two x16 slots? My understanding was that most mid to high end motherboards had two x16 slots but the second had a physical limitation of x8 when in Crossfire/SLI.

Third, will I need a new power supply? I currently use a 650W PSU and estimations suggest that my entire system would require around 600W with both 6970s. I'm not sure that cutting it so close is wise.

My setup:

MOBO: Gigabyte P67A-UD4-B3
CPU: Intel i5-2500K @ 4.5Ghz
GPU: ASUS HD 6970 2GB DirectCU II
RAM: Corsair Vengeance 8GB 1600Mhz
HDD: Samsung Spinpoint F3 1TB
PSU: Corsair HX650