How to Overclock Raspberry Pi 4 to 2.0 GHz

Yesterday I played with my new “ICE Tower CPU cooling fan” for Raspberry Pi 4 which cools the board just great but is clearly over the top. Regular reader and commenter m][sko mentioned it was possible to overclock Raspberry Pi 4 to 2.0 GHz after a firmware upgrade. That looks like a perfect task for my new fansink!

I’ve upgraded both the firmware and operating system:

sudo rpi-update
sudo apt dist-upgrade

1 2	sudo rpi-update sudo apt dist-upgrade

then edited /boot/config.txt as root (sudo) to add the following lines to boost the maximum frequency to 2.0 GHz:

force_turbo=0
arm_freq=2000
over_voltage=6

force_turbo=0

arm_freq=2000

over_voltage=6

Do not try to set force_turbo=1, as while it would allow to further boost the voltage, it will change a fuse in the chip, and it will void your warranty.

We can now reboot the board to validate the settings, and check those are applied:

vcgencmd get_config int | grep "arm\|over"
arm_freq=2000
over_voltage=6

vcgencmd get_config int | grep "arm\|over"

arm_freq=2000

over_voltage=6

Good. At idle the frequency is lower, but that normal:

vcgencmd measure_clock arm
frequency(48)=666826176

1 2	vcgencmd measure_clock arm frequency(48)=666826176

Voltage is set to 1.0335V:

vcgencmd measure_volts
volt=1.0335V

1 2	vcgencmd measure_volts volt=1.0335V

over_voltage will decrease or increase the max voltage in decrements/increments of 0.025V steps. The range -16 to 8, or 0.8V to 1.4V.

Let’s run sbc-bench.sh as we did previously, and monitor the temperature with rpi-monitor:

sudo /bin/bash ./sbc-bench.sh -c
WARNING: this tool is meant to run only on Debian Stretch or Ubuntu Bionic.
When running on other distros results are partially meaningless or can't be collected.
Press [ctrl]-[c] to stop or [enter] to continue.


sbc-bench v0.6.7

Installing needed tools. This may take some time... Done.
Checking cpufreq OPP... Done.
Executing tinymembench. This will take a long time... Done.
Executing OpenSSL benchmark. This will take 3 minutes... Done.
Executing 7-zip benchmark. This will take a long time..../sbc-bench.sh: line 600:  4724 Killed                  taskset -c 0 "${SevenZip}" b -mmt 1 >> ${TempLog}
 Done.
Checking cpufreq OPP... Done.

It seems neither throttling nor frequency capping has occured.

Memory performance:
memcpy: 2547.2 MB/s 
memset: 3651.0 MB/s (0.8%)

7-zip total scores (3 consecutive runs): 6900,6877,6939

OpenSSL results:
type             16 bytes     64 bytes    256 bytes   1024 bytes   8192 bytes  16384 bytes
aes-128-cbc      83479.79k   102077.25k   110821.72k   112916.14k   113631.23k   113541.12k
aes-128-cbc      83514.12k   102155.14k   110784.17k   112935.59k   113573.89k   113382.74k
aes-192-cbc      67566.13k    86925.76k    95294.38k    97361.58k    98189.31k    98331.31k
aes-192-cbc      75028.43k    90016.62k    96037.97k    97670.83k    98301.27k    98178.39k
aes-256-cbc      68036.63k    79945.09k    84813.82k    86112.60k    86035.11k    86338.22k
aes-256-cbc      61634.20k    77697.69k    84171.18k    85799.94k    86406.49k    86474.75k

Full results uploaded to http://ix.io/1PxG. Please check the log for anomalies (e.g. swapping
or throttling happenend) and otherwise share this URL.

sudo /bin/bash ./sbc-bench.sh -c

WARNING: this tool is meant to run only on Debian Stretch or Ubuntu Bionic.

When running on other distros results are partially meaningless or can't be collected.

Press [ctrl]-[c] to stop or [enter] to continue.

sbc-bench v0.6.7

Installing needed tools. This may take some time... Done.

Checking cpufreq OPP... Done.

Executing tinymembench. This will take a long time... Done.

Executing OpenSSL benchmark. This will take 3 minutes... Done.

Executing 7-zip benchmark. This will take a long time..../sbc-bench.sh: line 600: 4724 Killed taskset -c 0 "${SevenZip}" b -mmt 1 >> ${TempLog}

Done.

Checking cpufreq OPP... Done.

It seems neither throttling nor frequency capping has occured.

Memory performance:

memcpy: 2547.2 MB/s

memset: 3651.0 MB/s (0.8%)

7-zip total scores (3 consecutive runs): 6900,6877,6939

OpenSSL results:

type 16 bytes 64 bytes 256 bytes 1024 bytes 8192 bytes 16384 bytes

aes-128-cbc 83479.79k 102077.25k 110821.72k 112916.14k 113631.23k 113541.12k

aes-128-cbc 83514.12k 102155.14k 110784.17k 112935.59k 113573.89k 113382.74k

aes-192-cbc 67566.13k 86925.76k 95294.38k 97361.58k 98189.31k 98331.31k

aes-192-cbc 75028.43k 90016.62k 96037.97k 97670.83k 98301.27k 98178.39k

aes-256-cbc 68036.63k 79945.09k 84813.82k 86112.60k 86035.11k 86338.22k

aes-256-cbc 61634.20k 77697.69k 84171.18k 85799.94k 86406.49k 86474.75k

Full results uploaded to http://ix.io/1PxG. Please check the log for anomalies (e.g. swapping

or throttling happenend) and otherwise share this URL.

Let’s go to the log to check the maximum temperature and actual frequency during 7-zip test:

System health while running 7-zip multi core benchmark:

Time        fake/real   load %cpu %sys %usr %nice %io %irq   Temp   VCore
15:11:29: 2000/2000MHz  3.17  14%   1%  12%   0%   0%   0%  48.7°C  1.0335V
15:11:52: 2000/2000MHz  3.28  85%   2%  83%   0%   0%   0%  52.1°C  1.0335V
15:12:34: 2000/2000MHz  4.43  96%  48%  47%   0%   0%   0%  53.1°C  1.0335V
15:12:54: 2000/2001MHz  4.21  83%   3%  79%   0%   0%   0%  52.6°C  1.0335V
15:13:37: 2000/2000MHz  4.96  95%  40%  54%   0%   0%   0%  52.1°C  1.0335V
15:13:57: 2000/2000MHz  4.61  82%   3%  79%   0%   0%   0%  52.6°C  1.0335V
15:14:39: 2000/2000MHz  4.92  95%  37%  57%   0%   0%   0%  52.1°C  1.0335V

System health while running 7-zip multi core benchmark:

Time fake/real load %cpu %sys %usr %nice %io %irq Temp VCore

15:11:29: 2000/2000MHz 3.17 14% 1% 12% 0% 0% 0% 48.7°C 1.0335V

15:11:52: 2000/2000MHz 3.28 85% 2% 83% 0% 0% 0% 52.1°C 1.0335V

15:12:34: 2000/2000MHz 4.43 96% 48% 47% 0% 0% 0% 53.1°C 1.0335V

15:12:54: 2000/2001MHz 4.21 83% 3% 79% 0% 0% 0% 52.6°C 1.0335V

15:13:37: 2000/2000MHz 4.96 95% 40% 54% 0% 0% 0% 52.1°C 1.0335V

15:13:57: 2000/2000MHz 4.61 82% 3% 79% 0% 0% 0% 52.6°C 1.0335V

15:14:39: 2000/2000MHz 4.92 95% 37% 57% 0% 0% 0% 52.1°C 1.0335V

Broadcom BCM2711 processor Arm Cortex-A72 cores were indeed clocked at 2.0 GHz, and the temperature went as high as 53.1°C, so we still have a good safety margin here.

Raspberry Pi 4 Overclock 2.0 GHz Temperature — Click to Enlarge

rpi-monitor chart actually shows a peak at 55°C, but still 30°C from the 85°C temperature limit of the processor.

Let’s see how much performance we’ve gained against running Raspberry Pi 4 at the default 1.5 GHz frequency.

	Raspberry Pi 4 @ 1.5 GHz	Raspberry Pi 4 @ 2.0 GHz (overclocked)	Ratio
memcpy	2636.2MB/s	2547.2MB/s	0.97x
memset	3707.9MB/s	3651MB/s	0.98x
OpenSSL AES-256-CBC 16K	64744.11k	86338.22k	1.33x
7-zip	5454	6905.33	1.27x

Raspberry Pi 4 Overclocked Benchmarks — Relative performance of Raspberry Pi 4 @ 1.5 GHz vs Overclocked Raspberry Pi 4. Note OpenSSL score has been divided by 10 to show all results in the same chart

Memory benchmarks are basically the same meaning the bandwidth is not limited by the processor, but for other benchmarks, we get 27% to 33% performance improvement which mostly matches the theoretical 33% improvement we ought to expect.

If for some reasons, you’d like to have higher memory bandwidth, you could mess up with sdram_freq and over_voltage_sdram as explained in RPi overclocking options.

Jean-Luc Aufranc (CNXSoft)

Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his job as a software engineering manager, and starting to write daily news, and reviews full time later in 2011.