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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?

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5
  • There must be a register somewhere that will give you the clock speed.
    – Alex Chamberlain
    Commented Jul 26, 2012 at 19:42
  • Note that the instructions that came with my Pi explicitly mentioned that overclocking might make some components too warm.
    – Thorbjørn Ravn Andersen
    Commented Jul 28, 2012 at 16:20
  • Why did you change the title to something irrelevant to the question? I've rolled the change back until you explain because it made no sense to me.
    – Jivings
    Commented Jul 30, 2012 at 7:34
  • @Jivings: It doesn't cover the load anymore. My question received an answer on how to determine the MHz, as well as fixing issues with /config/boot.txt. Perhaps you can set a better title?
    – Sjaak Trekhaak
    Commented Jul 30, 2012 at 9:28
  • What do you mean? This question has already been answered. You've accepted otakun85's answer as correct. If you have another question then ask a new one.
    – Jivings
    Commented Jul 30, 2012 at 11:04

6 Answers 6

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66
+50

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If this doesn't exist, then your Raspbian is outdated.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.

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14
  • 3
    BogoMIPs is not a very good indicator of performance. There must be a better way.
    – Alex Chamberlain
    Commented Jul 23, 2012 at 20:33
  • @AlexChamberlain It is not a good indicator of performance, but is a good indicator of clock speed. Otherwise there is no substitute for running benchmarking code.
    – Darren Wilkinson
    Commented Jul 23, 2012 at 21:05
  • I tried the above, but to no result. The BogoMIPS keeps staying at 697.
    – Sjaak Trekhaak
    Commented Jul 25, 2012 at 8:14
  • 1
    @SjaakTrekhaak Did you reboot after changing the config? I have tried this and the BogoMIPS is always just under the clock speed I set in the config.
    – Darren Wilkinson
    Commented Jul 25, 2012 at 8:22
  • 1
    @SjaakTrekhaak Maybe you should try something posted here: raspberrypi.org/phpBB3/viewtopic.php?f=63&t=11810
    – keiki
    Commented Jul 27, 2012 at 12:09
16 
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.

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1
  • I think it's kHz. Mine (started today, still mostly untouched) says "700000".
    – ygoe
    Commented Apr 17, 2014 at 21:24
9

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
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2
  • 3
    lscpu doesn't work. The 800Mhz you have are the FSB of your quad core(I think). On Rasp I get the following: Architecture: armv6l Byte Order: Little Endian CPU(s): 1 On-line CPU(s) list: 0
    – keiki
    Commented Jul 26, 2012 at 18:10
  • 2
    dmidecode is not available; E: Package 'dmidecode' has no installation candidate
    – Sjaak Trekhaak
    Commented Jul 27, 2012 at 8:06
2

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 ^^

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1

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
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-4

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!

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2
  • 1
    OP how to know the current MHz, not how to change it.
    – NULL
    Commented Apr 8, 2016 at 16:36
  • 1
    This only answers half the question..
    – Steve Robillard
    Commented Apr 9, 2016 at 9:07

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