I bought GTA 4 via Steam and I've noticed that about 45 mins to an hour in, the game randomly starts stuttering. I figured it was probably because the settings were high so I turned them down and it still stutters. I turned V-Sync off and it helped a bit, but the stuttering still happens. I'm not sure what the problem is and from what I've heard it's a fairly common problem on PC. Is there any fix?
Have you tried running contig.exe [it's a Microsoft tool] and defragging your game directory? You can Google it for a full tutorial....Not saying that it will positively help,but it did boost the game's performance in my case. Hope this helps.