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Pi Zero Overclocking & Cooling

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I want a 10% overclock and keep my Pi Zero W cool.

The plan

  • Generate a baseline for temps and cpu speed without heatsink
  • Generate temps and cpu speed with typical heatsink
  • Generate temps and cpu speed with bigger heatsink

The tools

  • 15mm x 15mm x 2mm copper shims
  • thermal pads
  • typical raspberry pi heatsink
  • random other heatsink I found in a box

The Video

Overclock Settings

Once you’ve installed Raspbian to your SD Card, you want to open your Boot partition and find the file config.txt. At the bottom of this file we want to add the lines

arm_freq=1100
over_voltage=8
sdram_freq=500
sdram_over_voltage=2
force_turbo=1
boot_delay=1

 

arm_freq=1100 The value here corresponds to how many MHz the CPU will be clocked at.
over_voltage=8 Beginning with 1, each step increases the voltage supplied to the CPU by .25V. So a value of 8 results in supplying 1.4V to the CPU instead of 1.2V
sdram_freq=500 The value here corresponds to how many MHz the RAM will be clocked at.
sdram_over_voltage=2 Beginning with 1, each step increases the voltage supplied to the RAM by .25V.
force_turbo=1 When set to 1 the Pi will run at its max frequency of 1GHz, unless overclocked then it will run at the value found in arm_freq=
boot_delay=1 The value here will delay the kernel loading by 1 second, 2 seconds requires a value of 2.

Making the script

Now we have to use our terminal. The commands we want to test are below

This one measures your CPU Temperature

vcgencmd measure_temp

And this one spits out your CPU Speed in Hz (divide by 1000 to get MHz)

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

For the stress test I’m going to use SysBench. The test we’re running is

sysbench –test=cpu –cpu-max-prime=10000 –num-threads=1 run >/dev/null 2>&1

What this does is runs a test on the CPU which calculates all the prime numbers between 0 and 10000. This will max out our CPU in a way we normally wouldn’t under normal conditions.

Download link for the testing script: rPiZeroWTempTests

Or you can just copy and paste the script from here. Open your preferred text editor, paste the contents, give it a name and make sure to name it with the extension .sh

#!/bin/bash
vcgencmd measure_temp
sudo cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq
sysbench –test=cpu –cpu-max-prime=10000 –num-threads=1 run >/dev/null 2>&1
vcgencmd measure_temp
sudo cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq
sysbench –test=cpu –cpu-max-prime=10000 –num-threads=1 run >/dev/null 2>&1
vcgencmd measure_temp
sudo cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq
sysbench –test=cpu –cpu-max-prime=10000 –num-threads=1 run >/dev/null 2>&1
vcgencmd measure_temp
sudo cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq
sysbench –test=cpu –cpu-max-prime=10000 –num-threads=1 run >/dev/null 2>&1
vcgencmd measure_temp
sudo cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq
sysbench –test=cpu –cpu-max-prime=10000 –num-threads=1 run >/dev/null 2>&1
vcgencmd measure_temp
sudo cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq

You will have to also modify the properties of the script to allow it to be executable. To do this we use (assuming you named it test.sh)

sudo chmod +x test.sh

And finally we run the test by typing in the command

sudo ./test.sh

The Results

pi zero overclock

 

 

 

 

 

 

 

 

 

Now go have some fun! Good luck breakers!