I tried 1080p HD source encoding with Intel HD graphic 4000 i7-3520M (ivy bridge) on ubuntu linux, however, the sample_encode_drm runs at only ~40fps avg with TU=1, and the CPU usage is about %66 of one core.
However, according to this test, intel hd graphics 4000 should reach the speed of over 100fps:
I've also rebooted to windows and encode with mediacoder, the result is also ~40fps.
How could I increase encoding speed? use another CPU?