These graphs show the GPU usage patterns of the Flash Player plugin for Firefox and Chrome, respectively. The test involved playing a 30-second HD Facebook video.
As the graphs show, Firefox uses over 40% GPU during playback. After playback, (sitting paused), it drops to idle or near-idle.
Chrome uses much less GPU, as shown in the second graph. The
2nd play was obtained by using the Play Again button. Even though it is slightly higher than the first play, both times through use significantly less GPU resources than Firefox.
Both browsers have the latest installation/version of Flash player, and are running on Windows 7 x64 with Windows Aero enabled. The GPU is an Intel integrated card. Rebooting changes nothing.
Why the discrepancy?
No memory graphs, but Chrome's total usage (with nothing else running) was approximately 1/2 of Firefox's total usage.