Hi,
There isn't a hard and fast limit, TG2 can use as many as there are available. However in practical terms there comes a point where using more processors doesn't improve render time and the increased memory usage of multiple threads isn't worth it. That point probably comes around 12-16 processors or cores. It depends a little bit on the scene.
If you're thinking of buying a new machine I would suggest getting as many processors or cores as you can afford right now, because even if TG2 doesn't fully utilise them all now it will as we improved the threading code. There still aren't many machines with more than 16 cores, although you can get 24 core ones. Well, 12 cores with hyperthreading at least.
Regards,
Jo
