The Q9550 runs at 2.83 Ghz. The i7 950 runs at 3.07 Ghz. But, when the i7 uses hyperthreading, each thread only gets 1/2 of a core, so each WU runs at 1.535Ghz which is considerable less than 2.83 Ghz on the Q9550 and why it takes 7K seconds on the i7 versus 5.6K seconds on the Q9550. While I haven't tried it, I would assume that if I turned off hyperthreading, it would finish a WU in about 3.5K seconds.