Since we are testing Processors here, let's take a look at the CPU Scores churned out in 3D Mark 06:

3D Mark 06's CPU Test is very well programmed in terms of multi-threading so you can see the 2.66GHz Core 2 Quad outperforming the 2.93GHz Core 2 Duo by close to 60%.

CineBench is another benchmark well-programmed to utilize multi-processors and is based on the CINEMA 4D software.

Here, the QX6700 outruns the X6800 by 48%.

FutureMark PC Mark 05 CPU Performance comparison:

QX6700 scores 14% higher here.