Hmm.I had the 890FXA-GD65 and it could do x16/x16.They are practically the same board except for SLI support and voltage changes for the CPU but I don't see why the 990FXA can't do x16/x16.It might be SLI related but i'm not sure.
Either way you won't be able to notice a difference between x8 and x16.The performance loss is only around 10%.
PCI Express Gen2 refers to the second generation of the PCI Express standards ( PCIE 2.0) so PCI Express 2.0 is the same the PCI Express Gen2
MSI refers to that both PCI Express slots are Gen2 X16 but when a second GPU is populated one of the PCI Express slots will be routed as x8.
whatever, the 8800 ultra, GTX 580 use the same PCIE 2.0 standards...
and benchmarks indicates that there's a slight difference in performance isn't noticeable unless you run a 3D Mark or something like that .. you get more bunch of numbers...
Just for future reference the GTX580 is a much more powerful card than the 8800 Ultra.Which means that it has a lot more bandwidth.Technically it would be more hampered by the x8 slot than a 8800 Ultra but still the difference of a x16 and x8 slow is very minimal.
i'm just laughing out loud, did you read my post above ? i said " there's a slight difference that isn't noticeable is 3% being noticeable ? you won't notice it while gaming you'll notice it if you run a benchmark program
@ purple stank, look at the video OP posted and you'll find the answer about the GTX 580 full bandwidth...
@ OP, now you already know the difference, there's no difference and if there is it's just logical