The MagPi - February 2020

07

Take it to the max
Now we’re going to boost the gpu_freq and
take the CPU to its highest setting. This enables
Raspberry Pi to run at its current maximum speed.
Use Nano to edit the config.txt file again, this time
setting the arm_freq to 2147 and gpu_freq to 750:

over_voltage=6

arm_freq=2147

gpu_freq=750

The gpu_freq oversees a range of settings:
core_freq, h264_freq, isp_freq, and v3d_freq.
The core_freq setting adjusts the frequency of
the GPU processor. It influences CPU performance
because it drives the L2 cache and memory bus.
The default value is 500, and 750 is the highest
we can set it and still had a Raspberry Pi 4 run. We
have also had Raspberry Pi 4 boards fail to boot at
this speed, and others quickly slowed down from
overheating or undervoltage. You are unlikely to be
able to maintain this speed for the long term and
your mileage will vary.
Save the file and exit Nano (CTRL+O and
CTRL+X). Reboot and your Raspberry Pi is
hopefully running as fast as it can.

08

Recover from black screen
We have started a Raspberry Pi at speeds of
up to 2.147GHz but some of our devices failed to
boot, and others showed Undervoltage Warnings
(thus reducing the speed). Eventually, we settled
for arm_freq=2000 in config.txt. Our engineering
team told us that the benefits from gpu_freq
are marginal at best, and it should be removed if
Raspberry Pi 4 fails to boot.
Your Raspberry Pi will most likely fail to boot at
some point when overclocking. See ‘Overclocking
problems’ for more information on recovery.
Otherwise, have fun and we hope you've enjoyed
this excursion into overclocking.

#uncomment to overclock the arm. 700 MHz is the default.

over_voltage=6

arm_freq=2000

config.txt

001.

002.

003.

Language: Bash magpi.cc/github

DOWNLOAD

THE FULL CODE:

Top Tip

Documentation

See the ‘overclocking options in config.txt’ page on

Raspberry Pi’s website for detailed information on all

overclocking options. magpi.cc/overclockingoptions Firmware

warning icons

Under certain circumstances, the Raspberry Pi

firmware will display a warning icon on the display,

to indicate an issue. If you see these icons routinely

appearing, you should reduce the overclocking

speed. There are currently three icons that can

be displayed:

Undervoltage warning

If the power supply to the Raspberry Pi

drops below 4.63 V (+/-5%), this lightning

bolt icon is displayed.

Over temperature warning (80–85°C)

If the temperature of the SoC is between

80°C and 85°C, this icon is displayed. The

ARM core(s) will be throttled back in an

attempt to reduce the core temperature.

Over temperature warning (over 85°C)

If the temperature of the SoC is over 85°C,

this icon is displayed. The ARM core(s) and

the GPU will be throttled back in an attempt

to reduce the core temperature.

We’re going to use the

config.txt file to set a

new upper limit for the

clock frequency

TUTORIAL

Overclock Raspberry Pi 4 magpi.cc 37