it should work. AFAIK all nvidia card (including the latest series) should work properly with PCI-E 1.x since most nvidia cards are using PCI-E 2.0 standards. so far on the 6k series (and most 5k series) of the radeon using PCI-E 2.1 standards which often conflict with PCI-E 1.x standards. the problem mostly are solved with BIOS update but some old mobo doesn't have the update since it's manufacturer already ceased the support for it.
with your resolution you should be able to max out most games out there with frame rates above 30FPS. your card will only struggle to games that are very demanding such as crysis and metro to name a few