The first two SiSoft2007 tests (processor and multimedia) do take the additional 2MB of L2 cache featured on the E6700 into account. As you can see the overclocked E6700 processors are much faster thanks to a 200MHz frequency gain and the extra cache. Nevertheless, the overclocked E6300 was able to defeat the non-overclocked E6700 processors.
The Super PI and PCmark2005 tests also take the larger L2 cache of the E6700 into account. Despite operating 840MHz higher than the standard E6700 processors, the overclocked E6300 was only able to match the E6700 performance-wise in Super PI.
The PCmark2005 processor test placed the overclocked E6700 processors ahead of the E6300, while the E6300 was able to outperform the non-overclocked E6700s. Again the 965P-DS3P running standard settings was easily able to match the ASUS 975X and 965P motherboards.