Well if you really want to see what it can do i made a personal review on www.frozentec.com , go to the review section and read.
1280x1024 - at this resolution you should be able to max out the games, i do not know about gta4, but the ones i tested run with flying colors, also to ad, avatar will run at that resolution with all max out, crysis warhead also, and i doubt that gta4 won't work with max settings. Also i overclocked my card easy, and you can control the fan speed from the soft(catalist control center) witch you need to download from www.sapphiretech.com