I've had a PC with an Intel D945PVS Motherboard for several years now. It is PCI Express 1.0a compatable and worked well with my ATI X700 Graphics card. Two days ago, the fan burned out and the card needs to be replaced.
I've read conflicting views about compatability with PCI Express 2.0 cards where ATI causes no problems but NVIDIA does, so I purchased an ATI FirePro V3700 compatable with PCI Express 2.0 (not 2.1).
I hope it works and am asking about compatability after the fact. I'm waiting for it to arrive, but would appreciate some hopefully positive news before installation.
I got my answer. The Ati FirePro V3700 graphics card arrived. It's PCI Express 2.0 and there was instant recognition. The install was very smooth and after checking out applications (heavily graphical), everything works perfectly. I'd heard that 2.x Nvidia cards have problems with 1.0a, but this wasn't a problem with me since I always use ATI. As usual, ATI didn't let me down. I don't know how PCI-e 2.1 would work but ATI 2.0 is perfect.