The benchmarks and energy consumption are partially dependent upon the default setting of the base clock (bClk). It's supposed to be set at precisely 100.0 MHz, but some manufacturers put it slightly higher in order to end up higher in the benchmark stats. A higher bClk ensures better performance, but it also increases energy consumption. Gigabyte additionally increases the clock frequency of the integrated GPU in the BIOS, which you can clearly see in the 3DMark results on the next page. We're not huge fans of this "cheating", since it unfairly influences benchmarks and can be misleading for consumers.
We made a list of what the bClk is with the default settings, and the result you see below. Particularly Gigabyte and ASRock are often guilty of setting their motherboards to run at 100.9 MHz. The ASRock Z77 Extreme 11 runs at exactly 100.0 MHz.