[SOLVED] New motherboard graphics test

[ticojohn]

I just installed a new motherboard ( Gigabyte GA-H81M-H ) with an Intel i5 4460 processor. I ran glxgears to test the graphics display rate and go the following result.

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john@JohnBoy:~$ glxgears
Running synchronized to the vertical refresh.  The frame rate should be
approximately the same as the monitor refresh rate.
377 frames in 5.0 seconds = 75.387 FPS

Not surprising as my monitor refresh rate is 75 Hz.

I then ran the test with vblank_mode = 0, as suggested on a blog I read, and got the following result.

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john@JohnBoy:~$ vblank_mode=0 glxgears
ATTENTION: default value of option vblank_mode overridden by environment.
ATTENTION: default value of option vblank_mode overridden by environment.
39607 frames in 5.0 seconds = 7921.256 FPS
40283 frames in 5.0 seconds = 8056.519 FPS

Now, I'm pretty darned sure that my on board graphics and my LCD monitor are not capable of that high of a frame rate. So what does that number (~ 8000 FPS) really represent?

[stevepusser]

Why not that high a rate? That's a very simple animation, and doesn't depend on what your monitor can do.

Try enlarging the window to see if the rate drops, too.

[ticojohn]

Why not that high a rate? That's a very simple animation, and doesn't depend on what your monitor can do.

Try enlarging the window to see if the rate drops, too.

Okay. I guess I am just too hung up on old school teaching. Yes indeed, when I expand the glxgears window the frame rate drops considerably. Near full screen size and I get about 1400 FPS. Still seems really high. Guess what I really don't understand is the apparent de-coupling from the vertical blanking and still getting the signal "framed". That's not how I learned about all that some 50 years ago. Guess I should just be happy that my on board graphics seems to perform well.

And by the way, I think you were the one that told me there shouldn't be issues with Jessie on the Haswell processor. You were correct sir. The only issue I had was when I booted Stretch amd64 (just to try it out), from an old hard drive. There was an issue with the Realtek internet chip set. Installed the Realtek firmware and everything is cool. As long as i686 is available I probably won't bother to upgrade my Jessie i686 installation to amd64. It does everything I want it to do.

Thanks Steve

[ticojohn]

Okay. Did some book learnin ! LOL. Now I get it. The GPU is capable of pushing out a whole bunch more frames than that defined by the sync rate. Doesn't mean however that they are actually being displayed. Read this article which pretty much cleared it up for me.

http://www.avadirect.com/blog/frame-rat ... resh-rate/

Thanks again Steve

[Bulkley]

Glxgears is still around? It was always fun to play with but pretty much useless. Glxgears is not a Benchmark For troubleshooting purposes use glxinfo.