If we were to judge the Core 2 Quad based on the two first SiSoft2007 benchmarks, we could conclude prematurely it's a hell of a buy but obviously there is more to it.
Although the E6700 is clocked at 2.66GHz and the Q6600 runs at just 2.4GHz, the Q6600 has four cores versus E6700s two. The end result was three times more performance for the Q6600 over the E6700 which is obviously very significant. Despite this, Super PI showed the Q6600 to be the slowest processor of the bunch as this program does not support quad-core processors. PCmark2005 also showed no performance gains for the Q6600 over the dual-core processors tested.