Hello guys, today we are going to discuss the necessity for overclocking the famous SBC Raspberry Pi 3 (Not the raspberry pi zero), Different overclock values for different Operating systems, the peak of overclocking of this SBC and what does each rate mean.
Overclocking : Why ?
The most basic answer would be to get more bang for your buck, A perfectly overclocked RPi3 can run 1080p/30fps ezpz, Whereas the stock values make the Pi stutter after 1280×720 resoulution.
Another great advantage you get from overclocking is that you will get to know the insides of your Pi, A raspberry pi is the number #1 testing board in the world. Tolerance to overclocking is high with rPi hardware.

Overclocking : The Values that we’ll tinker with…
dtoverlay=sdhost,overclock_xxxx : These values determine the MicroSD card reader rate. Default if 50Hz. Overclocking SD reader on Raspberry Pi 3 results in 25%-40% boost. Warning : Please make sure you have a UHS-SD card (Ultra High Speed) of Class 8 or 10. Lower segament sd-cards will get damaged.
arm_freq :Defines the clock rate of the main ARM CPU. The default is set to 1000MHz, And we will play with this value a lot depening on the need of CPU in our tasks. For HD-Video decoding we don’t need that much freq, But for gaming and mining purposes, We need the most it can churn out.
sdram_freq : The speed of SDRAM, greater speeds can decrese stutter, provide more data flow. Downsides includes the need for Heatsink on RAM. Default is 400MHz
over_voltage : The voltage starts at 1.2V and adjusts up or down in 0.025V steps. 0 is equal to 1.2V, the minimum -16 is 0.8V, and the maximum 8 is 1.4V. Voltage starts to help when running core/GPU/SDRAM at or over 500MHz. Warning : Ensure you have a capable power supply before over-volting anything. Cheap power supply hurt more than they do good.
There is a complex mathematical relationship between the clocks for the GPU core and the individual GPU components. Setting these without understanding their relationship may result in running a component faster or slower than intended. By including avoid_pwm_pll=1 and force_turbo=1, we can overclock the individual gpu components.
core_freq : The clock speed of GPU processor core. We tinker with it when we need more rendering power.
v3d_freq : The speed of OpenGL 3D Graphics Processor.
h264_freq : The speed of x264 video decoder. It is used while video-playback. Stays idle in Emulation and mathematical needs.
gpu_mem : The memory of Raspberry Pi 3 dedicated for GPU purposes. The more it is, More it helps in video-playback. Incresing it means decresing the RAM for system use.
Config 1 : Best config for video performance (Kodi) on RPi3 :
arm_freq=1275
core_freq=500
sdram_freq=575
over_voltage=4
sdram_schmoo=0x02000020
over_voltage_sdram_c=4
over_voltage_sdram_p=6
dtoverlay=sdhost,overclock_50=100 #Remove if doesn’t boot.
temp_limit=85
avoid_warnings=1
v3d_freq=500
h264_freq=333
gpu_mem=512
Config 2 : Best config for Processing Tasks (BitMining, Emulation) :
gpu_mem=400
arm_freq=1350
over_voltage=5
sdram_schmoo=0x02000020
sdram_freq=500
core_freq=500
gpu_freq=400
temp_limit=80
avoid_warnings=1
Config 3 : Most Stable Rates for long run :
arm_freq=1200
core_freq=500
gpu_freq=500
sdram_freq=500
over_voltage=2
dtoverlay=sdhost,overclock_50=100 #Remove if doesn’t boot.
temp_limit=85
avoid_warnings=1
Help, I see a yellow Power Surge sign on the right top corner of my display, what is going wrong ?
The Yellow icon indicates that you board is throttling due to lack of Amps, The most recommended fix is to replace the Power supply and the power cable. Choose a 2.5A+ PSU, and the cable should be not more than 15 Inches, The bigger the cable, the more power fades away.
My Pi does not boot, what can I do ?
The values mentioned above are well tested on a vast number or pies (yum), But in case you need the orignal values, you can put a # (comment sign) before each command in config.txt, This will make your Pi run on default settings and also help you isolate the flawed command.