Sgt. Hugo Stiglitz

Hey guys and gals, Thanks in advance for reading this. Sorry if this has already been posted; I searched through most of the posts and couldn't find a definite resolution. I bought a new PC recently, specifically to prepare for ArmA II. I have an intel i7 920 at 2.66 GHz, an NVIDIA GTX 285, 12 GB of DDR3 tri-channel RAM. So, here's the problem. With all settings maxed, I seem to get very decent frame rates (~30+ most of the time). The problem? Stuttering. The game runs beautifully for about 5-7 seconds, then stutters, then runs for 5-7 seconds, then stutters, etc. (I'm sure most of you are familiar with the problem). It just becomes very troublesome when trying to gun for a helicopter or something, because I'm constantly freezing up when I should be blasting whatever is infront of me into oblivion. I asked a few guys in the game I was in, and they were very helpful; they suggested turning off Hyperthreading, which is apparently in my BIOS. Is there anything else I can do to minimize/prevent stuttering? If hyperthread disabling is my only option, would someone be kind enough to tell me how to do it? I'm still basically completely clueless when it comes to the inner workings of PCs. I don't know how to access or modify my BIOS/hyperthreading... I don't even know where or what it is! Any help anyone could give me would be sincerely appreciated, please and thank you.

For what it's worth, I was in the Infantry myself, and during marksmanship training we were told specifically to "breathe in normally, exhale 1/3 to 1/2 of the breath, hold your breath at that point, and take the shot".