The Performance-Per-Watt, Efficiency Of Intel/AMD/NVIDIA GPUs On Open-Source Drivers

Given the raw frame-rate for this Xonotic Linux gaming test and the AC system power consumption from the WattsUp USB power meter polled by the Phoronix Test Suite, here's the auto-calculated performance-per-Watt.

Delivering the best performance-per-Watt of the large variety of GPUs tested on the open-source drivers was the Radeon R9 270X graphics card. Coming in just behind the R9 270X were the other recent AMD Radeon GPUs from the Radeon HD 5770 and newer (sans the R7 260X exception due to using the older firmware). With the proprietary Catalyst driver, there's higher power efficiency when using the GCN graphics cards, but as the Radeon open-source stack isn't as extensively tuned as Catalyst the performance-per-Watt was more or less flat from the Evergreen series and newer for the mid-to-high-end GPUs.

The Haswell HD Graphics 4400 and 4600 performance-per-Watt was roughly in line with the efficiency of the Radeon HD 4000 series graphics cards.

Under Nouveau, the Kepler GeForce GTX 680 and 760/770 graphics cards were delivering higher performance-per-Watt than the older GeForce graphics cards even though they were all running without re-clocking support.