[-spek-]

I have an AMD XP ATHLON 3200 - on a NF-7 Nforce 2 mobo -
I have 2 slots of 512 sticks of DDR ram total of 1024 GB
ATI RADEON 9800 Pro 128
SBAUDIGY soundcard
Serial HD

and I have every possible drivers installed .

HERE'S THE PROBLEM:
In my BIOS setting under Standard settings for my cpu I have 3 options - 2500 or 3200 setting or custom. When I select the 3200 my computer starts up fine and loads xp okay - When I'm playing games (Especially HL2 and Source mods) my computer crashes to the desktop or it automatically shuts itself down. This sucks hardcore and I don't know why it does it. Well when I change in my BIOS setting the setting from 3200 to 2500 it runs fine. NO PROBLEM WHATSOEVER. The thing is, it runs at 2500 speeds which I don't want it to. What's going on? Could it be that my CPU gets to hot and shuts itself down. Bad BIOS settings
Driver needed? Anything that can help to cause this crashing memory error and game crashing/restarting problem. Any Suggestions? or fixes?