just built my son a computer with the 8700k and paired it with a Gigabyte Z370 Aorus gaming 5 board,,,installed windows 10 and noticed using CPU-Z that idle speed was 800mhz...i know other CPU's will run full speed after adjusting a setting in the BIOS..so i emailed Gigabyte and this is the response:
Unfortunately this was the Intel processor designed to protect processor have longer life. There has no option to force processor runs at full speed all the time. You may try use over clock settings but it also runs in idle if no application is running in OS.
GIGABYTE technical support team.
is this true???
Seeing an idle speed of 800 MHz is absolutely normal and expected. This is Intel Speedstep Technology saving power when the system has little to do. When the system is made busier, the clock speed will be automatically increased to meet the need. Further, if needs continue, once the system reaches the highest external clock speed, additional increases in clock speed will occur within the processor, where temperatures will allow, This is Intel Turbo Boost Technology increasing performance where it can. There *are* methods to force the system to run at "full speed" all the time (though Gigabyte appears to be saying that they do not expose any of these methods), but this would be an absolutely silly waste of power. Further, your processor would be running much hotter and likely would be unable to take advantage of Intel Turbo Boost Technology.
Hope this explains it,
You can "force" the 8700K to run at it's maximum speed (do keep in mind, maximum means respecting the limits imposed in BIOS/firmware, such as max multi/turbo, TDP) by selecting the High Performance power plan in Windows. The CPU will try to boost as much as possible even when idle. You can also force it (basically overclocking) to run an all core 4.7GHz from BIOS with what is called MCE, multicore enhancement. I wouldn't recommend it at all, it overvolts the CPU and can prove to be unstable under stress.
I would allow the 8700K to run normally as it doe with the Balanced power plan if I were you. You can definitely test High Performance, but don't expect better framerate in games or anything of the sort. The 8700K is smart enough to know when to boost and how much, and fast enough to offer you great performance without forcing higher clocks.
Excellent explanations by both above. 800MHZ on the desktop in idle state is normal for the default balanced plan and an excellent one for most people. If you have two displays, or if you can simply run game in windowed mode with CPU-Z also running you will notice as your game is running (and the instant it's launched) that your clock speeds are now where they should be.