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:

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

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:

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

Voltage is set to 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 as we did previously, and monitor the temperature with rpi-monitor:

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

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.

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 GHzRaspberry Pi 4 @ 2.0 GHz (overclocked)Ratio
OpenSSL AES-256-CBC 16K64744.11k86338.22k1.33x
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.

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