Today I've noticed something really weird:

When I execute

vblank_mode=0 glxgears

I get:

38885 frames in 5.0 seconds = 7776.864 FPS

39279 frames in 5.0 seconds = 7855.745 FPS

39096 frames in 5.0 seconds = 7819.048 FPS

And wen I execute:

vblank_mode=0 primusrun glxgears

I get:

7813 frames in 5.0 seconds = 1562.430 FPS

8459 frames in 5.0 seconds = 1691.648 FPS

8464 frames in 5.0 seconds = 1692.777 FPS

So, without primusrun/optirun I'm getting 500% more FPS. How is this possible?

Does this mean that I'm using my nvidia chipset most of the time and for gaming (the only thing I use primusrun steam) I'm using the intel one?

How could I fix it?

1 Answer 1


This is normal.

Running primusrun "command" will always get your nVidia card to render the program, not the other way around. The issue here is simply that glxgears is not a benchmark.

You should benchmark with something else. Try supertuxcart or xonotic. Or even better, try an actual game you wish to play.

You pretty much have nothing to fix, at least as far as using the nVidia card is concerned. =-)

  • You were rigth, cs:go with primus: 45~55 , without: 20~35 Oct 22, 2015 at 16:52
  • Good thing it's sorted! I had the same experience with glxgears vs Left4Dead2.
    – Stunts
    Oct 22, 2015 at 20:20

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