Raspberry Pi 3 Overclocking and Stability Testing

I recently ordered and took delivery of the new Raspberry Pi 3, with the intention of letting my son use it as a desktop computer replacement.

Web browsing with Chromium works pretty well, but was still a little bit laggy on Javascript-heavy sites, and I had hoped to eek a bit more performance out of it.

Inspired by this guy, I tried upping the clock speed, but needed a way to stress test it, and at the same time, check for stability. On x86 equipment, I would use Prime95 to fill that role: it has the CPU perform calculations, and compares the results with a known reference. If they don’t match, then the CPU has made an error (due to heat, voltage, a flipped bit somewhere in RAM or cache, etc).

Existing stress test software that I’ve encountered for the Raspberry Pi doesn’t seem to care about the integrity of the calculations performed. And since Prime95 doesn’t run on ARM processors, I came up with my own solution: a quick and dirty BASH script that will run four simultaneous iterations of a command that calculates a million digits of pi. It then makes sure the results match, outputs the time it took to execute the commands, and the temperature of the CPU core, and loops until it’s aborted with CTL-C, or it encounters an error.

Here’s that script:

My results were pretty disappointing, by the way. The stock clocking of the CPU, 1.2GHz, appears to be the highest speed this chip is able to handle stably.

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