Originally Posted by Zhivago
I have a fairly powerful system with a quad core Phenom II 3.2 Ghz, am ATI 4890, and 4 GB ram.
However, for some reason GTA IV is absolutely crawling at around 2-20 FPS (literally!) and even I find that I get no improvement when I lower graphical settings all the way down to 640x480. It used to run great when I had a 4870 512MB card..
All I can think of is that the additional 512 MB of VRAM on this card is hurting me, since I only have 32 bit windows. Does this sound like a possiblity? Anyone in here running it fine with <= 3 GB ram?
EDIT: drivers are the same.. heck, I didn't even touch them, I just swapped in the new card.
Start with reinstalling the drivers. This is the first no-no with ATI. Never change cards without uninstall / reinstalling their drivers.
You may want to move to x64 because you are losing alot of system ram now with x86 OS. You are only likely to be addressing about 2.8Gb of your ram now with a 1GB GPU. When I went to the GTX 280 I stopped using x86 OS for the same reason.
I think the driver reinstall will sort things though.