GFXBench 3.0: Battery Life
We use the GFXBench 3.0 battery life test to examine GPU thermal throttling, because the T-Rex workload generates a lot of heat. At the end of the test, GFXBench creates a nice diagram that plots battery charge (green line) and performance (blue line) versus time. Since performance is directly linked to the GPU core frequency, this diagram characterizes the device’s GPU thermal throttling over time.
During this test, we use an infrared camera from Seek Thermal to measure the surface temperature of the device. The camera sensor is a vanadium oxide microbolometer type with a 12μm pixel pitch. It has a resolution of 206x156 for a total of 32k thermal pixels, which can detect long-wave infrared of 7.2-13 microns. The camera is rated to be accurate to within 2% at 100 °F, and uses a “black body” shutter that passes in front of the lens periodically for self calibration.
The maximum skin temperature of the rear cover is recorded during the test and compared to other devices in a chart. The thermal image is also provided, because it shows how a device’s structural design helps or hinders heat dissipation.