PCI-E Question

Hey guys, well my motherboard has 2 PCI-E x16 slots, but only one runs at x16 speed while the other runs at x4 speed. It says on the box that Crossfire is supported, I was wondering would anyone know, if I ran 2 cards in Crossfire, how much the second card running in an x4 speed slot would affect performance?

The motherboard is an Asus M5A97 EVO R2.0

GPU would be MSI R9270X

I've tried to Google it but couldn't really find any good answers.


It should work, but you may get a bit of a performance hit with the second GPU running at only 4x. I know 8x is enough and won't bottleneck but I'm not so sure about 4x. 

I do know that as a general rule of thumb if you wanna use Crossfire or SLI you should get a 990FX chipset motherboard.

One other thing to consider is do you really want to use Crossfire in the first place? I have used Crossfire/SLI in the past and it is a pain in the ass. Some games preform better. Like a 70%-85% increase in framerate, Most see an increase of around 50%. Some even see a decrease in framerate. Not to mention all the driver headaches associated with multi-GPU setups (Driver issues, power consumption, heat and noise.) It is usually best, and especially in your case with only one 16x slot, to just buy a better single GPU.

I have same mobo and am running 2 7950s so ya it works. I cant compare to what it would be like at 2x pci-e  x16 but it definitely improves performance not so much on older games but Tomb Raider really likes it, Crysis3 is better, but my [email protected] runs at 90+ percent(on Crysis3) so I am getting bottlenecked for sure. Still I am happy and cant wait to upgrade my CPU and MOBO.