[paki123]

specs
video card Ati 5770 x vapor gpu 940 mhz memory 1305 MHz.
Processor i5 2500k 3,7 ghz
Ram 8 gb kingston 1600 mhz CL 9
Power supply 500 W
Motherboard p8p67
Case Haf 922
GTA IV Patch 1.0.7.0
i play on 1600x700 other details medium even if I play on the resolution of 1200 x 600 lag again
soory for bad english.

[Exxon]

Post your full graphical settings.
You probably have the Night Shadows on High, turn them off as they are a performance killer and it looks quite ugly anyway.
Besides that, you should lower the sliders a bit to improve your framerate.
As last, if you have any mods installed, you could try to remove them as mods influence performance.

[paki123]

[Exxon]

Yeah, indeed.
Lower the car density to 40 or something the other sliders at around 35 or something like that.
But most important, just completely turn those night shadows off!

Besides that, you could try the commandline switch to improve your performance.
And if really nothing helps, reinstall the game and use patch 1.0.4.0. That's the best one performance-wise.

[unc13bud]

plus it looks like the original poster has modified the game. which is why he has those vehicle details up so high? i agree.