This doesn't warrant a new thread, and this is the closest thing to a GTA IV that I can post in, so I'm putting it here.
Most, if not all of you, know GTA IV is a terrible port. Like, most PCs that run great games can't run IV because the port was messy, considering Rockstar was working with a new engine. Well stuff man, do I got news for you.
I was on Reddit recently and I finally figured out a way to get it to run better. It's not the best, but it's good enough.
First things first, you need to disable "Clip Capture" in the "Game" tab in the menu. This thing is constantly recording the game so you can save the last twenty seconds of gameplay in case something insane happens. Secondly, you should turn down View Distance, Detail Distance, and Vehicle Density. These can be huge performance hogs. I find the best settings to be the ones used on the console, if you have a great CPU though, go ahead and crank that stuff up.
Console Settings:
View Distance: 21
Detail Distance: 10
Vehicle Density: 33
Now, GTA IV was a console port - so by default it has some settings that limit it's potential. Assuming you use Steam, right-click GTA IV and go to properties, then hit the "Set Launch Options" button. Enter:
-norestrictions -noprecache -novblank -nomemrestrict -percentvidmem 100
and save.
"These commands basically takes off the kiddy/safety gloves. It basically tells the game to quit acting like it's still restrained by a console with limited resources. norestrictions essentially enables the other options, no precache (preloading and storing stuff in buffer instead of closer to real time) novblank (don't empty the video buffer inbetween every frame) nomemrestict (don't limit the amount of ram you utilize) percentvideomemory100 (access all video memory - since on a pc, typically memory isn't shared)"
Now it starts to sound a bit forgetey, but trust me. You need to turn your graphics settings up. You can try out each setting alone, or turn each setting up to the next option, whatever. The thing is, GTA IV relies on the CPU a lot. What you need to do is offload some of that to your GPU, and by turning up the settings you're doing exactly that.
For reference, my specs are:
1600x900 (60Hz)
Intel i5-2310 @ 2.9Ghz
AMD Radeon HD 6850
8GB RAM
Before all these tweaks, I was running GTA IV on Medium-High settings with a framerate of 30FPS. Now I practically run it with every option on "Very High" - but with Anistrophic x8, since the difference between x8 and x16 is very minimal - with a framerate of 30FPS.
Seriously, this stuff works. If you have a better rig than me, you're set.