i am having the same problem. my gtx295 does not support my monitors native SXGA resolution 1400x1050 (i hate you nvidia) so it downsizes the resolutio to 1024x786 which is the maximum of what it cas set it to (i hate you even more nvidia) Radeons never had problems with this monitor i checked 3 of my radeon (even the crappiest X800XL)see the 1400x1050 even without the drivers. and this resolution is not even listed in the nvidia driver, and it refuses to create a custom resolution as well.
I know this resolution is a bit non standard but there are monitors that have it and there is NO REASON why nvidia sholdnt be able to support it especially a GTX295!
dont hate people who rip you off,cheat and get away with it, learn from them