We tested the 16 Intel X79 motherboards in combination with an Intel Core i7 3960X processor, 4x 2 GB Corsair Vengeance DDR3-1600 RAM, an AMD Radeon HD 6850 video card, a Western Digital Raptor 74 GB hard drive, and Windows 7 x64.
Many manufacturers applied a clever trick in their BIOS. As you were able to read in our Sandy Bridge-E review, the speed of the turbo mode depends on the number of active cores. In default a 3960X runs at 3.3 GHz. With all cores enabled, the turbo mode will put the speed of the CPU officially at 3.6 GHz. With only one or two cores active the turbo mode goes up to 3.9 GHz.
Since the processors are completely unlocked, motherboard manufacturers are free to determine their own turbo settings. A large number of the motherboards in this test have turbo mode clocked all the way to 3.9 GHz, with all cores enabled. This obviously improves performance, but also leads to higher energy consumption. Please note that this is the default setting that you often are not able to turn off, should you wish to do so. In the SiSoft Sandra Dhrystone test you can immediately see which motherboards are using this turbo trick.