Several tests are carried out for each firmware revision: power draw is measured at both idle and peak loaded conditions a thermal image of the board is captured at idle and after 60 seconds of sustained load and the self-reported SoC temperature and CPU clock speed are tracked during a 10-minute synthetic workload - glxgears to push the GPU and stress-ng in four-thread FFT mode to stress the CPU - followed by a five-minute cool-down period. Thermal imagery is taken using a FLIR C2 thermal camera, processed to correct for minor variations in environmental conditions over the course of the testing and to set a fixed scale for ease of comparison, then overlaid on an edge-enhanced visible light image of the board to allow for easy recognition of individual components. This is connected to the Raspberry Pi 4's USB Type-C power input. Power is provided from an Aim TTi E元03R bench-top power supply, which has calibrated and accurate current measurement facilities, set to a 3A maximum current at 5V. It is run without the bundled case, using the latest version of the Raspbian Linux operating system - but with manual control over its firmware. The subject for this test is a retail-release Raspberry Pi 4 Model B 4GB, taken from an official Raspberry Pi Desktop Kit. There's only one way to prove the efficacy of these updates, however, and that's with direct testing.

It also drew some criticism for its higher-than-expected power draw and, correspondingly, heat output - something the engineers at the Raspberry Pi Foundation have been working to address in a series of firmware updates.

The Raspberry Pi 4 launched earlier this year to critical acclaim, thanks to upgrades including but not limited to a more powerful processor, the first new graphics processor in Raspberry Pi history, true gigabit Ethernet connectivity, and PCI Express-connected USB 3.0 ports.

Flir raspberry pi