Physx card question

[oalfyo]

My current rig is a ASrock extreme3 gen3 with a i5-2500k, and msi twin frozrIII gtx 570. I have a pny gtx 550ti lying around so i decided to install it as a dedicated physx card for fun.... while running fluid mark benchmark i notice a 20% increase in performance. my question is concerning my motherboard. If not running sli and just the physx addition does my mobo run 2 pcie x8 or does my 570 still get the pcie x16 and the 550ti become pcie x8, if the later were the case and the 550ti were running x8 it would be no problem, i just dont want to slow down my 570 for the minor 5-10 fps difference.

 

[aicom]

Both cards are running at x8 per your motherboard's specification sheet.