peebeds

Hey guys, Its probably been asked a million times before, but can anyone help me with my lagging issue. System specs are: Abit AW9D Max with a quad core Intel Q6600 running at 2.6 and 4GB of OCZ Memory. Graphics is an ASUS 7850 OC running at 1440x990 ARMA is installed on an SSD, with Windows 7 Ultimate 32bit on a WD Raptor. Internet connection isnt brilliant, we average about 1mb dl and .5 up DayZ runs fine, Ive never had an issue before, but Ive just recently started getting into the actual ARMA2 game itself and specifically, Wasteland. Problem is that I can play fine for about 20mins to half an hour, then the FPS drop to virtually nothing. All the textures and models turn into big blocks, wheels look square as opposed to round and playing the game is impossible, this is in MP. Ive not tried any SP missions, just the training stuff which seemed to work fine. Ive gone through quite a few setup tips etc, turned most of the graphics settings to default, Post Processing and AA are off, and Ive added the '-CPUcount=4 ' to my shortcut properties, but nothing really seems to help. I know my system isnt top spec and from what I have read, ARMA is quite CPU intensive, so could that be the issue? Ive got a copy of Win7 Ult 64bit which I just need to get round to installing, I can then bung another 4gig of ram in there, but dont really want all the hassle of re installing everything! Any help would be HUGELY appreciated. Cheers.