[SOLVED] i5 8600k throttling at 70C

Jun 7, 2019
I have my i5 8600k on a MSI Z370 A-PRO motherboard with an EGVA AIO water cooler.

I've set my Clock speed at 5000MHZ, but when I run Cinebench R20 it runs at 5000 for about 20 seconds then throttles down to around 4500 MHZ. I am using CPUID Hardware Monitor to monitor clock speeds and temperatures. I did adjust to voltage to 1.280, but all my other voltage settings are left on auto. I'm nervous to start adjusting those, when I don't really understand what they do. I've also adjusted my fan curves so the fan goes to 100% at 65C, just to keep the temperature down in the case. I am under the impression that this chip should be able to comfortably tolerate temperatures over 80C.

Is my CPU being limited by the power delivery? How do I find out?
if temps are over 80C they could get worse as coolant temps rise under a heavy 1 hour load, depending on your radiator capacity...(thermal runaway; as coolant warms, it cools less, leading to yet even warmer coolant, etc...)

You could easily set an all core action of whatever multiplier you are comfortable with commensurate with your cooling capacity...

If above 80C, I'd be hesitant to stay at 5 GHz...; check temps of Prime95 v 26.6/small FFTs (vice default Blended mode), the defacto gold standard for thermal testing of CPUs... (A system will crash within two or three minutes if core voltage is insufficient for the desired all-core turbo clock speed, at least mine did in testing of my 7700K looking for 4.8 GHz at default core voltage...)