I want to buy the ZOTAC ZT-50401-10L GeForce GTX 550.
Which is PCI Express 2.0 x16.
I am a bit concerned about this because the official tech support said:
The Motherboard Asrock G41M-VS3 R2.0 has a 16X PCI-Express slot first generation, and works well with this current generation either be ATI or NVidia, do not install a second generation card because it won’t be detected.
Solution:
PCI-E 2.0 devices are fully backwards compatible, so you should have no problems. The hardware will only function at PCI-E 1.0 speeds, though.
They probably recommend you don’t use them in first generation slots for performance reasons, but the GTX550 shouldn’t come anywhere near the maximum speeds of 1.x. I have seen both 8800GT’s and 9800GTX’s working fine in PCI-E 1.0 slots.