CPU frequency drops after system upgrade

English Hardware
1

I’m not sure after which exact upgrade the CPU freq drops, but it was around 1.5 months ago. The CPU freq was near the 2.3 GHz line before, but now it drops below 1.1 GHz:

image

I haven’t felt any noticeable impact. Just out of curiosity, does anyone know the reason? I guess it might come from kernel update or some CPU scheduling tool’s policy change? Or some hardware vulnerability patch?

My system environment is:
Operating System: openSUSE Tumbleweed 20231006
KDE Plasma Version: 5.27.8
KDE Frameworks Version: 5.110.0
Qt Version: 5.15.10
Kernel Version: 6.5.4-1-default (64-bit)
Graphics Platform: X11
Processors: 12 × Intel® Core™ i7-9850H CPU @ 2.60GHz
Memory: 31.0 GiB of RAM
Graphics Processor: Mesa Intel® UHD Graphics 630
Manufacturer: LENOVO
Product Name: 20QTS00B00
System Version: ThinkPad P1 Gen 2

2

Why do you expect permanently high frequencys? The frequency is load dependend. And if the load is low the CPU frequency drops to 800MHz. You can set your CPU to a permanently high freq value. But the power draw, heat and noise of fan will increase without real need…

3

I my 30+ years as a software engineer and hardware fanatic, I’ve never worried (or even checked) CPU freq.

You state there’s no impact.

So then, what’s your concern?

4

No, as stated in the post, I’m not worried, just “out of curiosity”. It’s perfectly fine if this drop is not an issue, but since I noticed it, I wonder what caused the sudden change :eyes:

I think there are patches for certain hardware vulnerabilities which have impacts on CPU performance. But it’s not clear to me what these effects manifest themselves in. So I thought the drop was caused by some patch, but I couldn’t find any news related. That’s why I want to ask here.

1 Like
5

Frequency of idle cores changed recently, no change for active cores:

erlangen:~ # inxi -Cy132
CPU:       Info: 8-core model: AMD Ryzen 7 5700G with Radeon Graphics bits: 64 type: MT MCP cache: L2: 4 MiB
           Speed (MHz): avg: 1538 min/max: 400/4673 cores: 1: 2998 2: 400 3: 2999 4: 400 5: 3032 6: 2998 7: 2999 8: 400 9: 400
             10: 2998 11: 400 12: 400 13: 2993 14: 400 15: 400 16: 400
erlangen:~ #

Low idle values are a good thing:

erlangen:~ # cpupower frequency-info
analyzing CPU 0:
  driver: amd-pstate-epp
  CPUs which run at the same hardware frequency: 0
  CPUs which need to have their frequency coordinated by software: 0
  maximum transition latency:  Cannot determine or is not supported.
  hardware limits: 400 MHz - 4.67 GHz
  available cpufreq governors: performance powersave
  current policy: frequency should be within 400 MHz and 4.67 GHz.
                  The governor "powersave" may decide which speed to use
                  within this range.
  current CPU frequency: Unable to call hardware
  current CPU frequency: 400 MHz (asserted by call to kernel)
  boost state support:
    Supported: yes
    Active: yes
    Total States: 3
    Pstate-P0:  3800MHz
    Pstate-P1:  1700MHz
    Pstate-P2:  1400MHz
erlangen:~ #

However pstates are unchanged.

https://www.google.com/search?q=amd+ryzen+pstates

6

If there was an actual problem, then I’d be curious.
Yea, gamers get into the frequency thing pretty heavy, so understand that.
(Maybe inquire at a gamers forum or your motherboard /cpu manufacturer’s forum).

Anyway, if the latency in ramp-up does not effect the interactive feel, it’s best to have the frequencies as low as possible. (and you wrote, “I haven’t felt any noticeable impact.”).