As far as I know, Reason can't use HT, so it doesn't use all of your 8 virtual cores.
One of my friends does have an AMD FX8100, which does have "real" 8 cores, no hyper-threading. Reason still only used 4 on his system. DSP meter maxed out, while the overall system performance was at 50%. I remember, how PH stated about the HT thing, from my experience though, it doesn't use up to 8 real cores either.
Last edited by emotica; 2012-11-17 at 17:34.