My motherboard is MSI G41-M-P26. It has a PCI-e 1.1x16 card compatible expansion slot. I know that, PCI-e 2.1 is backward compatible. My question is, now, if I use 6750 GPU, which is probably PCI-e 2.1x16 card, what will be the effect on gaming performance (mainly on Pixel fill rate, Texture and Bandwidth)?