FSX, as well as most other programs, doesn't support hyperthreading. Just multiple cores. So if you were to disable ht in the bios, my theory, is that you'd see 4 cores fully running, rather than 8 cores/threads, with only 4 of them half running. I've never tried. If you had a single core cpu with say, 4 threads with hyper threading enabled in bios then you'd see 4 cores/threads with one core running at 25% (3 cores/threads would just sit there idle.) With ht disabled, you'd see one core at 100%. One game that I believe takes advantage of hyperthreading is, Trackmania Nations Forever. Its free... Anyways...I'm no expert. so if anyone sees anything wrong with my thoughts, please let me know. That's why we're here...Right?