after reading some reviews, particularly the aceshardware, I sum up like this: (1) it appears, multithreaded applications benefit from HT significantly. That is exactly what we have expected. (2) in some cases applications benefit from the new cpu with HT switched off (compared to a non-HT cpu at same clock speed). Why is this? Are there other architectural changes in the cpu? (3) in some cases single threaded applications seem to benefit from HT. Why is this? May be related to the next point. (4) in some cases concurrently executed applications benefit from HT. Why is this? Is it not a contradiction to the fact that hyper threads run in the same VM context? Bearing in mind that the performance gain in the cases (2), (3), (4) is usually a few percent only, but the question remains.