Hacking Pi firmware to get the fastest overclock

Since boosting my Pi 5 from the default 2.4 GHz clock to 3.14 GHz on Pi Day, I've wanted to go faster. Especially since many other users have topped my Geekbench scores since then :)

In March, Raspberry Pi introduced new firmware that unlocked frequencies above 3,000 MHz for overclocking. This summer, NUMA Emulation patches boosted performance another 5-10% through memory access optimizations.

But even with a golden sample Pi 5, I haven't seen anybody go much beyond 3.1 or 3.2 GHz. The problem seemed to be power supply—the Pi's firmware limits the SoC to a maximum of 1.000V.

There is an over_voltage_delta option which works with DVFS to boost voltages a bit—but that is also capped at 1.000V.

After emailing back and forth a bit, GitHub user jonatron beat my 3.14 GHz overclock quite handily, pushing his Pi up to 3.3 GHz, but without attempting a full Geekbench 6 run.

His blog post (linked above) explains some of the process, but after talking a bunch, he agreed to let me release a bit of code that enables the overvolt hack. It is now available in my pi-overvolt repository, along with a description of how to use it—and copious warnings.

The problem is, if you hack the firmware's voltage limits, you void your Pi's warranty. I'm not sure if it's detectable, especially the way it's being done here... but there's a good chance you'll burn up your Pi's SoC even if you know what you're doing.

I didn't burn up my Pi (luckily), and I made this video documenting my journey to a stable-ish 3.4 GHz overclock, resulting in the current world record Geekbench 6 score on a Pi 5.

If you want to replicate my setup, here are all the parts I used:

• Raspberry Pi 5 'golden sample' (the one that was most stable out of the 10 Pi 5's I own)
• USB Fan Heatsink Peltier Cooling Module (Amazon affiliate link)
• Bottom heatsink plate from EDATEC Fanless Heatsink Case
• Noctua 5V 140mm Fan (Amazon affiliate link) inside this 3D printed stand
• Argon PWR GaN 27W USB-C power supply (Amazon affiliate link)
• Extra thermal pads (Amazon affiliate link) to conduct heat from PMIC to Peltier cooler

For the world-record 3.4 GHz Geekbench run, I ran my custom kernel with the NUMA Emulation patch (linked earlier in this post) applied, and followed the instructions to set a higher voltage in my pi-overvolt repo.

Update: Since posting this information, I also found out about another great guide to overclocking and the PMIC's limitations on the Pi 5—see SkatterBencher #77: Raspberry Pi 5 Overclocked to 3000 MHz.