How do I determine the current MHz?

Question

I've been trying to get an accurate reading of my Raspberry Pi's MHz, since I overclocked it in /boot/config.txt

My /boot/config.txt is as following:

pi@raspbmc:~$ cat /boot/config.txt 
arm_freq=900
gpu_freq=350
disable_overscan=1

List of things I already tried:

1. Look at the /proc/cpuinfo - No MHz listed, does have BogoMIPS at 697, while CPU speed is set at 900.
2. The sysstat package - returns 0.00 MHz.
3. cpufreq-info: no or unknown cpufreq driver is active on this CPU

Any ideas?

Answer 1

Updated (much has changed):

BogoMIPS is not useful for the new ondemand overclock config in raspi-config. It will provide 697 (which means 700MHz here) if you overclocked to 1GHz, because it is still in idle mode. 800 MHz are about 795.44 BogoMIPS .

maximum CPU frequence (e.g. when your CPU is under load)

sudo cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq

minimum CPU frequence (when your CPU is idle)

sudo cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_min_freq

current CPU frequence:

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

If this doesn't exist, then your Raspbian is outdated. Try updating it using apt-get update and apt-get upgrade

---

Overclock: Nowadays you can easily overclock the Pi with the help of raspi-conf to ondemand 1GHz at maximum, your pi may fail to boot afterwards.

Answer 2

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

That will give you your current speed in kHz. Divide by 1000 to get MHz.

Answer 3

I don't have a Pi running atm, but this command exists in my raspbian chroot. This is on my quad core desktop, which is currently somewhat idle so it takes in the governor setting (don't know whether this is available on the pi, i suppose not)

$ lscpu 
....
CPU-frequentie (MHz):  800.000
BogoMIPS:              5800.03
...

Another one, with some caveats: this does is not very reliable as it uses information reported by the bios and it is not available in the current raspbian wheezy repository (i'm posting because maybe it will someday):

$ sudo dmidecode  | egrep "Max Speed|Current Speed"
Max Speed: 2900 MHz
Current Speed: 2900 MHz

Answer 4

If you want to see the frequency in real time, I recommend using this command:

watch -n1 vcgencmd measure_clock arm

When overclocking, usually the temperatures also matter a lot, so this would be the command to read those:

watch -n1 vcgencmd measure_temp

Usually, you will see the clock being on a static level (around 600MHz when using the Pi 4), but if you open up another shell and run a sysbench, you will see the clock going for the maximum frequency. I hope this helps ^^

Answer 5

For 4 Cores Raspberry Pi 3B

find /sys/devices/system/cpu/cpu[0-3]/cpufreq/scaling_cur_freq  -type f | xargs cat | sort | uniq -c

Answer 6

You can type sudo raspi-config in LXTerminal, use the arrow keys to navigate to "Overclock" and hit enter, hit enter again, and look at the MHz section under None. You're done!