GTA IV massive stuttering

Hello all im new here ive been searching around everywhere from steam forums to even LCPDFR Site to try & sort the issue out but no matter what ive tried its still not worked.

within a few minutes of going from 50+ FPS playing it starts to stutter bad to the point where its impossible to play properly

My Specs:

Windows 7 Ultimate x64

CPU: I5 3570k stock speed 3.50ghz

H100 Water cooled

Memory 16GB DDR3 1600Mhz

GFX : 660 x2 SLI Enabled

Sound :SB XFI Extreme

HDD 3TB Seagate SATA 6

Monitor RES 1920x1080

Steam copy of GTA IV

I Had lcpdfr 1.0c

i decided to completely reinstall windows 7 To see if it was any mod related issue but nothing, Ive installed fresh gta iv copy from steam without no mods at all stock game with just command line

-norestrictions

-nomemrestrict

ive also tried restrictApp 0 ive tried so many things to fix this issue different commandlines, Disabling Event log Services, All sorts, but nothing just dont understand what the issue is

Any other ideas would be greatful,

Thanks Mehmet