Any Ideas?

[TEF]

Third-party programs that supposedly "fix" crap like lag and whatnot are not to be trusted. Most of the time these "accelerators" do absolutely nothing and just eat up more CPU. Also, it's worth noting that just because your computer isn't "old" doesn't mean it doesn't suck. Anyway, do what Dan said and stop running everything when playing SA:MP. I used to have an .exe that got rid of unnecessary shit like dust, smoke, fire, etc. in order to lower game lag. I'll do some searching around and try to get that to you.