How to really check current cpu Hz?

Question

All programs I've tried seem to be listing Hz from cpu's specifications not actually checking what the current Hz really is.

for example a processor is marketed with 4GHz.But this is the max (unless you over/under/clock) and if the cpu isn't doing anything or is getting too hot it will throttle down.

The program always will say 4Ghz even when the CPU is at 2Ghz.I want to avoid this and know the real Hz.

What programs actually check current cpu hz and not just read cpu specifications?

http://askubuntu.com/questions/218567/any-way-to-check-the-clock-speed-of-my-processor ( sudo dmidecode -t processor | grep "Speed" ) — Rinzwind, Apr 08 '14 at 18:23
@Rinzwind I like this the most because it displays cpu hz ever ysecond. sudo watch -n 1 cat /sys/devices/system/cpu/cpu*/cpufreq/cpuinfo_cur_freq but I dont have cpu folder in cpu folder so I get no such file or directory.What should I do? — fdsfgdsdf, Apr 08 '14 at 18:39
ok but I would added it to the link 3 people accepted as duplicate ;) — Rinzwind, Apr 08 '14 at 18:40

score 16 · Accepted Answer · answered Apr 08 '14 at 18:38

16

You can easily check the current CPU frequency using the following command:

watch -n 0 "lscpu | grep 'MHz'"

You can also get the current cpu frequency with this command:

cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq

Most modern CPUs can adjust their clock frequency. The default governor on linux is "on demand" which keeps the clock speed low to save power when idle, and speeds it up to do work when needed.

Visit https://www.kernel.org/doc/Documentation/cpu-freq/governors.txt for further details.

answered Apr 08 '14 at 18:38

Sylvain Pineau

62,169

2

Is the governor not working? I always see 2000MHz. – fdsfgdsdf Apr 08 '14 at 18:40
open close several applications, start VMs, it will change. Or maybe close all of them and wait a couple seconds to see the idle speed – Sylvain Pineau Apr 08 '14 at 18:41
1

I really mean always (unless I overclock)the same even if cpu usage is 100% – fdsfgdsdf Apr 08 '14 at 18:44
Try forcing the powersave mode with echo "powersave" >/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor – Sylvain Pineau Apr 08 '14 at 18:47
There is a small exception..: some programs show the Hz as 2000.xxx where xxx is different on every boot (I guess boot) now it is 2000.175 Why does the xxx number change? – fdsfgdsdf Apr 08 '14 at 18:47
ok I will try it.How to revert to normal? EDIT: No such file or directory – fdsfgdsdf Apr 08 '14 at 18:48
replace powersave with ondemand, See the kernel doc for supported values (like performance) – Sylvain Pineau Apr 08 '14 at 18:50
Unofrtunately I couldnt try it because I get No such file or directory every time.Why is this? – fdsfgdsdf Apr 08 '14 at 18:54
cat: /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq: No such file or directory for a AMD Ryzen 5 3600 (12) @ 4.706GHz – xdevs23 Feb 21 '24 at 17:17
The path on my system is /sys/devices/system/cpu/cpufreq/policy0/scaling_cur_freq and /sys/bus/cpu/devices/cpu0/cpufreq/scaling_cur_freq – xdevs23 Feb 21 '24 at 17:20

How to really check current cpu Hz?

1 Answers1