Ty Orly, I havent OC'd anything as of yet, what are you usin to OC your cpu, is it a built in or dlded utiltiy, my pc is brand name w/out and OC utilities built in.
I had tried a card utility rivatuner but it was initially said by R* that this & other tuners could be causing the texture missing problem I was experiencing.. so I had removed it but still experience on these lower settings some texture loss, dunno if that is sys RAM at 2GB is the cause still, as they spec 2.5GB for Vista recommended specs..
I dint know about this "Fusion" :: is reading ::
I bought it overclocked. I dont really know much about over-clocking. But you should try the AMD Fusion Utility and select the "X" on the left hand side of the menu and select expert. Also there is a new beta 3 of Nvidia drivers that gives a good solid performance boost. See this thread.
http://www.gtaforums.com/index.php?showtopic=382627
Good Luck!