4 Replies Latest reply on Feb 11, 2018 2:36 AM by gordonq

    What is the Ryzen 2500u frequency range?

    natis1

      I just got my HP Envy x360 with a Ryzen 2500u and I am looking to get a longer battery life on Linux (Gentoo) by saving some power by underclocking it, and vice versa when the device is plugged in..

       

      lscpu reports the following about the CPU:

       

      CPU MHz:             1636.924

      CPU max MHz:         2000.0000

      CPU min MHz:         1600.0000

       

      cpupower frequency-info seems to confirm this:

       

      driver: acpi-cpufreq

      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: 1.60 GHz - 2.00 GHz

      available frequency steps:  2.00 GHz, 1.70 GHz, 1.60 GHz

      available cpufreq governors: ondemand userspace powersave conservative performance schedutil

      current policy: frequency should be within 1.60 GHz and 2.00 GHz.

                      The governor "conservative" may decide which speed to use

                      within this range.

       

      For reference my kernel is 4.15rc7 and I am using the "git" version of linux-firmware.

       

      Is this information correct? Every Intel CPU I have ever owned allowed me to downclock to 800MhZ. ARM is even better, allowing either 200MhZ or 100MhZ depending on the manufacturer. Furthermore, the maximum frequency seems low, especially compared to the 3.6GhZ boost clock promised for the 2500u.

       

      And if not, how can I get a larger frequency range?

        • Re: What is the Ryzen 2500u frequency range?
          gordonq

          get a laptop cooler imo will help. my hp x360 laptop can sustain over 3.0ghz on all cores at 65C (without any gpu loads of course)in benchmark. It can hit 3.15ghz on all cores for a short burst.Screenshot (5).png

            • Re: What is the Ryzen 2500u frequency range?
              natis1

              Thanks for the advice.

               

              Looking at your picture I can see you're running at a frequency above 2GHz, and I did some analysis and found my frequency range actually ranges from around 1.3GHz (which is still higher than I'd expect for a minimum but at least it's better than 1.6GHz), to upwards of 3.4GHz. This is great! But it seems like I can't control this behavior at all.

               

              Why is the CPU frequency range that I can set as an end-user limited from 1.6GHz to 2.0GHz?

               

              And what does setting this value actually do when the real range is larger?

            • Re: What is the Ryzen 2500u frequency range?
              gordonq

              oops I was wrong, all cores only can sustained at 3.0ghz for the first run in passmark cpu test. In cinebench stress test (8 threads) it started throttling after few runs when the temp hit 78-79C (one of the core freq dropped to 1.5ish ghz), and eventually, the temp hovered around 80C (in this 25w tdp config). The multithread score also dropped to about 550 from the initial 600.Screenshot (12).png