What I have read is that Raspberry Pi 4, or any version for that matter, will have variances between manufacturing runs so that using highest possible settings may result in boot failures or other problems. The default settings are conservative so some degree of overclocking will improve performance however don't assume that max or near max overclock settings found in an article will necessarily work for you.
Note: The quality and capacity of the power supply is important when overclocking since doing so will pull more power. If the power supply is unable to handle the current and voltage demands from overclocking, your Raspberry Pi will have unreliable performance.
Note: Thermal management and proper cooling is important to prevent CPU throttling due to increased temperatures. Heat sinks with a fan will probably be needed.
See this documentation on the
config.txt file and the various settings available along with suggestions for values. Raspberry Pi Documentation - The config.txt file
See as well this article from seeedstudio, How to Safely Overclock your Raspberry Pi 4 to 2.147GHz which also mentions this consideration when overclocking:
In most cases, overclocking is safe and will not void your warranty if done so in an appropriate manner. However, you should still be aware that there are several settings that will void the warranty by flipping a hardware switch inside your Pi:
- over_voltage greater than 6
- temp_limit greater than 85
See this post about
gpu_mem, How am I supposed to set GPU memory in RPi4? which mentions what is also mentioned in the above
config.txt file documentation, a recommended maximum of 76 for the Raspberry Pi 4. The above documentation also says the following"
To ensure the best performance of Linux, you should set gpu_mem to the lowest possible value. If a particular graphics feature is not working correctly, try increasing the value of gpu_mem, being mindful of the recommended maximums shown below.
This article, How to overclock Raspberry Pi 4, has a number of tweaks to the
/boot/config.txt configuration file for overclocking. The article also discusses power supply and heat management.
The article does note that when experimenting, you will probably end up with boot failures. The article mentions the following procedure should you have a boot failure due to changes to the
Most overclocking issues show up immediately with a failure to boot. If this occurs, hold down the SHIFT key during the next boot. This will temporarily disable all overclocking, allowing you to boot successfully and then edit your settings.
The above article mentions this about the
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.