i9-10850 won't run above 4800 MHz on Ubuntu mate 21.04

Question

My i9-10850 cpu that could go up to 5.20 GHz won't go above 4.8 GHz. I'm on Ubuntu mate 21.04.

CPU spec sheet: https://ark.intel.com/content/www/us/en/ark/products/205904/intel-core-i9-10850k-processor-20m-cache-up-to-5-20-ghz.html

I'm testing with stress and s-tui. Cpu is not throttling because of the temperature. Temperature never goes above 83C. The power is also stable at ~190W.

cat /sys/devices/system/cpu/intel_pstate/no_turbo

returns 0 which should mean that the turbo boost in on.

Turbo boost is allowed in Bios. I didn't do overclocking, only unlocked limits so it can go turbo for longer.

On my another system with the same cpu and OS I see the same behavior.

What can I do to fully utilize the 5.2 Ghz? I don't want to be changing voltages, just unlock whatever can be unlocked on the cpu.

s-tui with stress: https://ibb.co/XW8GxP6

bios: https://ibb.co/C65Mnvw

https://ibb.co/s3LbWGg

https://ibb.co/CHZpddr

https://ibb.co/pzGVXyL

Answer 1

Your link to Intel's product information states (emphasis mine):

Max turbo frequency is the maximum single core frequency at which the processor is capable of operating using Intel® Turbo Boost Technology and, if present, Intel® Thermal Velocity Boost. Frequency is typically measured in gigahertz (GHz), or billion cycles per second.

So here's a first hint there's more to this "turbo boost" classification.

Your 10th gen Intel CPU has several different max frequency classifications: Turbo Boost 2.0 2-Core: 5.0Ghz Turbo Boost 2.0 N-core: 4.7Ghz Turbo Boost 3.0 2-Core: 5.1Ghz Thermal Velocity Boost 2-Core: 5.2Ghz Thermal Velocity Boost N-core: 4.8Ghz

Stressing all cores, TVB gives you 4.8Ghz. Stressing max 2 Cores you can expect 5.1Ghz and if the stars align TVB will get you that 5.2Ghz peak.

All these boost clocks are only available if your power delivery is what it needs to be and if you dont hit thermal limits that cause throttling. This CPU can run very hot and requires high end cooling to hit its target frequencies.