I think the point that Mem was trying to get at is this is not a "generic" dual-core cpu problem. An example of that would be trying to run EQ1 with 2 cores enabled, the game runs extremely fast, and you may even get banned for "speed hacking" due to how fast your character moves. However, both CS and Quake4 work perfectly fine with dual-core meaning this is not a dual core problem but a problem with hardware instability. That could be drivers, or hardware settings or simply bad hardware. I do not think trying to disable dual core is the solution you should be aiming for here. I think you should be ensuring none of your hardware is overheating, monitoring all your power requirements via something like everest and trying to narrow down the piece of hardware that may be causing conflicts. Also with dual core you can run 2 instances in parallel to test your dual core cpu, but I've found in the past that running prime successfully does not mean a whole lot in the long run.