this is the same for me. But as far as I read in the forum here "detection" does not mean "using" - so TG2 does not seem to actually use all detected processors in rendering. What I do is slpitting up - I start 4 TG2 instances on one machine, each is given one processor to render with (in task manager, "Affinities") and that´s working fine!
cheers,
Steffen