thanks for the quick response.. also wanted 2 know how much performance loss will be there in running a pci-e 2.0 x16 card in a pci-e 1.1 x16 slot. also my current 9500 gt is pci-e 2.0 only and runs great.i suppose the 9500gt requires a psu wattage of arnd 450 W. will the 550 ti need more. i guess my psu is arnd 450 -500W.
The GTX 550 Ti is pretty weak, so it won't make much difference whether it's running on PCIe 1.1 or 2.0. A stronger card would run into a bandwidth bottleneck.
PS: The GTX 550 Ti is a pretty poor deal at least in most places (US and UK certainly).