So I've been doing a bit of investigating, and it turns out BF3 does indeed use HT rather well.
Messing around with a dual core i3 @ 4GHz and HT on and off changes FPS by more than 30-40fps! Then comparing the i3 with HT to an i5 without HT they produced practically identical results.
It seems BF3 only needs a chip with the ability to run 4 threads, it doesnt matter if 2 of them are virtual.
Anyway, its the first game I've come across that uses HT lol, and I know people have been turning it off to make it run smoother, as did I with my hex-core chip, but the dual core is smooth as butter with HT?!