ProDigit
Posts: 374
Joined: Tue Aug 30, 2011 1:24 am

Overclock Pi 3B+

Tue Aug 20, 2019 12:53 am

Just for my own reference,
They're mild overclocking settings (lines entered into /boot/config.txt), that also will make the pi run cooler at idle.

Pi 3B+ with GPIO screen hat, and case, 3 passive heat sinks on the top, and 1 on the bottom:

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arm_freq=1495
arm_freq_min=450
gpu_freq=515
gpu_freq_min=200
core_freq=530
core_freq_min=200
sdram_freq=600
sdram_freq_min=200
over_voltage=1
over_voltage_min=-3
sdram_over_voltage=1
sdram_over_voltage_min=-2
temp_soft_limit=70
Doing this, GLX gears gets me about 16.5-18.5% higher boost FPS than stock,
Or, when the thermal throttling kicks in, an equal than boost stock.
boost FPS, it takes about 15 seconds to reach thermal throttle in my case.

In GLX-Gears:
Stock BOOST FPS: 197 fps
Stock throttled FPS: 197 (CPU doesn't get hot enough running GLXGEARS to throttle down, inside my case)

OC BOOST FPS: 230-234fps
OC throttled FPS: 197fps
*EDIT: It appears that 'temp_soft_limit=70' is responsible for the rise in boost fps, due to the CPU down throttling at 60 to 1,2Ghz in stock form.


Pi 3B+ with open case, 3 passive heat sinks on the top, and 1 on the bottom:

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arm_freq=1510
arm_freq_min=500
gpu_freq=520
gpu_freq_min=300
core_freq=540
core_freq_min=300
sdram_freq=620
sdram_freq_min=300
over_voltage=2
sdram_over_voltage=1
temp_soft_limit=70
AVG BOOST and stock fps: 247 (25% increase, CPU reaches 70C in 100 seconds).

Check Voltage & Frequency:

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watch "vcgencmd measure_volts core && vcgencmd measure_clock arm"
To undo an overclock, or go back to settings you can either delete the line, or put a '#' (hash/pound sign) before the line.

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