In general, you'd prefer NOT to use HT cores on your i7. Blue hasn't specifically stated not to use HT cores but they did state that if you tweak the affinity mask, make sure it isn't using _only_ HT cores. Keep in mind that HT cores are a software-emulated logical core. The only real hardware cores on an i7 are cores 0, 2, 4 and 6. Hyperthreading was teh awesome on older CPUs (~30% gains on P4 CPUs) but with the limited support for multithreading in WoW and the more advanced i-Series CPUs from Intel, it isn't nearly as much of a gain and can, depending on your motherboard's implementation details, be a net gain of zero.

See this thread for data on games vs "mathy" apps. http://www.tomshardware.com/forum/261564-28-core