So I tried to run Grand Theft Auto IV on the pc a while back… it ran like crap! But, just today, I reinstalled it, and I went on the internet to see if I could find out how to run it in windowed mode, because on my old computer, games ran better in windowed mode. All I have to say about running GTA IV in windowed mode is WOW! When I ran it in fullscreen mode, I couldn’t minimize it without crashing either the game, or my whole computer. Plus, in fullscreen mode, the game just ran like crap all together. That changed almost 100% when I switched to windowed mode. I can alt-tab out of the game, and look up walkthroughs for the game… or do anything else for that matter. I can also run the game with all the graphics settings set to medium. It started out with everything set to high, but that made the game slightly jumpy, so I dropped to medium, and have been running smoothly now.

I can’t tell you the FPS though, because I don’t currently have anything installed that will tell me that. I might install Fraps though, and see if I can record a video later to show that I can run the game.

And now My system specs:
Microsoft Windows XP Pro X64 with SP2 (I don’t think x64 has SP3)
AMD Athlon 64 x2 5000+ 2.60GHz
4.00GB RAM
ATI Radion HD 3870 1GB Graphics card
I think that is about it.

In conclusion, I can run GTA IV in windowed mode at 1024×768 resolution with the graphics settings set to medium with fairly good performance.

update: and before anyone asks, I have stood still, got into a cop car chase, blew up a car, and gone though a couple of missions all with the same performance (the only exception is when I blew up the car, it only slightly lagged for a second or two)