Glxgears is not a Benchmark

For the uneducated computer user, glxgears looks like an OpenGL program that tracks FPS numbers. In fact, this is what it does but it does it on a rather low load scale. Low load you ask? How much computational power does it take to spin a gear in a 200x200 pixel box? People with a Radeon 9500 or better need to understand the following:

Debunking the Myth (radeon vs fglrx)

Your FPS numbers went up after you loaded the fglrx driver! This is not because the radeon driver "sucks." This is due to the activation of *HARDWARE* acceleration since the 'radeon' driver has no 3D acceleration. Your 'radeon' driver was using your CPU and the Indirect MESA OpenGL library. Your 'fglrx' driver is using your Radeon VPU. Imagine that!

Debunking the Myth (fglrx updates)

Your FPS numbers went up/down after you loaded the latest version! This is not because there was a change in the driver. Since the program is so wild and sensitive to load (since it barely uses any computational power), any 100+ FPS increase or decrease can easily be attributed to a music program or OpenOffice document you have open. You can also wildy change FPS in glxgears by simply unfocusing the window. Want a 1000FPS increase?? UNFOCUS THE WINDOW! Of course this is meaningless, since you can't enjoy Doom3 if you can't see the window. (Also it's meaningless since unfocusing the window does not necessarily give a speed improvement - on my Radeon 9200 + fglrx, I get 2007 FPS +- 2 FPS regardless of window focus or Open Office running).

Debunking the Myth (glxgears is a benchmark)

glxgears is not a benchmark.

You can use it to show that DRI works, but it does not even test that well. There's glxinfo or your Xorg.0.log to tell you if DRI was enabled as well.

Check fglrx install status

# fglrxinfo
# glxinfo
# vi /var/log/Xorg.0.log
# dmesg

Use any of those commands to view the status of the fglrx module. Did it initilize correctly? Did it load DRI? Look in those files. If glxinfo reports direct rendering as "no" or the OpenGL renderer as "Mesa", then you are currectly using software (un-accelerated) rendering.

Check if direct rendering is actually used

As a rule of thumb, currently (as of Dec. 2005) a modern PC (like a P4) can give about 900 FPS in glxgears without Direct Rendering enabled (ie. using only software rendering, which is done completely by the CPU). If you have a fairly recent graphics accelerator, glxgears should give you significantly more than 900 FPS if Direct Rendering is enabled and used.

If glxinfo shows that Direct Rendering is enabled, while glxgears performance speaks against this, check if the OpenGL libraries are installed correctly.