Originally Posted by Llamalama
I have a P55 so if I use the 4x slot for physx would it render my main 16x slot into 8x. Hope this makes sense.
I'm not certain...
It might, or it might not. I don't think the second slot was intended for a video card specifically. Capable? Yes. Intended- maybe. I'm thinking that the two slots *might* not be tied together- thus regardless if slot #2 is occupied or not, your primary one runs at x16.
Though I could be wrong- at the time those mobos were out your could get by running a card in an x4 slot for CrossFire. Not the best idea, but you could do it.
Either way, I don't think going from x16 to x8 will hurt your FPS much. I've not looked into it since the 8800 days, but from what I gather the PCI-e 1.0 interface offered more bandwidth than the cards could consume. I'd only assume the same holds true for the PCI-e 2.0 bandwidth.
In other words- I don't think dropping from x16 to x8 will hurt performance any. To the best of my knowledge, we've yet to saturate PCI-e x16 1.0 bandwidth yet, let alone the bandidth of PCI-e x16 2.0.