The breadth of the numbers is because some people tested with Turbo Boost on to show how the CPU would really perform, while others tested with it off so they could compare the QX9770 and 965XE at an unvarying 3.2 GHz. Turbo Boost automatically overclocks busy cores by 133 or 266 MHz when other cores are idle. It looks like the difference in single thread performance is due in almost even proportion to clock for clock (i.e.: both chips running at the same 3.2 GHz) speed improvements and the Turbo Boost overclocking.