GTA IV Weird lag that didnt happen before

[Huntsman]

So basically, after reinstalling windows my GTA IV started lagging badly..
Before reinstalling my windows  , i could play GTA IV without any lag on max, now it keeps lagging... It feels like it's working smoothly for 1 second and then it freezes, then working smoothly and freezes again...

/help?
Post Merge: July 29, 2012, 07:51:02 pmDxdiag


Time of this report: 7/29/2012, 20:49:46
       Machine name: RYTIS-PC
   Operating System: Windows 7 Professional 32-bit (6.1, Build 7600) (7600.win7_gdr.120401-1505)
           Language: Lithuanian (Regional Setting: Lithuanian)
System Manufacturer: INTEL_
       System Model: DH61WW__
               BIOS: IBA GE Slot 00C8 v1365 PXE 2.1 B
          Processor: Intel(R) Core(TM) i5-2500 CPU @ 3.30GHz (4 CPUs), ~3.3GHz
             Memory: 4096MB RAM
Available OS Memory: 3570MB RAM
          Page File: 1803MB used, 5336MB available
        Windows Dir: C:\Windows
    DirectX Version: DirectX 11
DX Setup Parameters: Not found
   User DPI Setting: Using System DPI
 System DPI Setting: 96 DPI (100 percent)
    DWM DPI Scaling: Disabled
     DxDiag Version: 6.01.7600.16385 32bit Unicode

Post Merge: July 29, 2012, 08:09:16 pmNever mind guys, seems like my PC wasnt using its ram to the full capacity. It finally works without lag.

I used the command bcdedit /set pao ForceEnable

[Borus]

Just out of curiosity, what graphic's card does your PC have?

[Huntsman]

Just out of curiosity, what graphic's card does your PC have?

ASUS EAH6850 1GB