Why would you disable them? I think windows only loads 1 thread per core untill you're using more cores than you have, then it goes to the threads. So since like video editiong or 3d modeling uses every core, the cpu will be at 100%, but like a browser only uses 1 or 2 cores, so either the first or the first and the 3rd threads will be active, since the even numbers are the secondary threads