How did we test +bClk values and BIOS versions?
We tested all Intel Z170 motherboards with an Intel Core i7 6700K processor, 8GB Corsair Vengeance DDR4 memory (clocked at 2133 13-13-13-31-2T), an OCZ Arc 240 GB SSD and a Corsair CX750M power supply. All tests were performed using Windows 8.1 x64.
All boards are tested at default settings, the way they came out of the box, with two exceptions. We enable both C-States and Intel EIST, two settings which limit power consumption. Manufacturers used to cheat a little by secretly increasing the bClk by a small amount. We and other review websites of course didn't like this practice very much and these days the manufacturers play fair and square. As you can see in the graph down below the maximum deviation we found is 0.5%.
One little trick many manufacturers do use is standardly making the Turbo-mode more aggressive compared to the Intel standard. The maximum Turbo-mode of the 6700K of 4.2 GHz should only be occurring when one core is in usage, according to Intel at least. Most boards however utilize something we call ''aggressive Turbo'', which in contrast to normal Turbo also scales up the clock speed to the maximum value when all cores are in usage. We can clearly see this in the CPU benchmarks on the next page. Of course you're always free to set an aggressive Turbo yourself. The motherboards with aggressive turbo are marked with a black colour in the graphs, while the motherboards without it are marked by a blue colour.
In the table down below you can find all the BIOS versions we used in this test:
|ASRock Z170 Extreme6||P1.40|
|ASUS Maximus VIII Ranger||0401|
|Gigabyte Z170X-Gaming 5||F2|
|MSI Z170A Gaming M5||1.40|
The next graph shows the default bClk values.