[clean install of slackware 12, using the default ati driver]

I am having trouble with the gl screensavers that came with slackware 12. The display of these screensavers are not smooth, but rather jerky. For instance, the 'euphoria' screensaver updates every second, or so, rather than continuously updating. This is not right.

I do have dri activated and am getting glxgears output in the 2000+ fps range as a user. FPS games, such as 'enemy territory' work well (except for an occasional arts issue (what's up with that?)).

I have not tried to run a screensaver as 'root', but I may try that to let me know if there is some strange permission issue.

Any thoughts?

Hmm... might be permissions. I had exactly the same problem on FC6 with a Nvidia GeForce 7950GT. I had to go into the /dev directory and do this

chmod a+rwx /dev/nvidia0
chmod a+rwx /dev/nvidia1
chmod a+rwx /dev/nvidia2
.
.
chmod a+rwx /dev/nvidia6

before Xscreensaver would work right with the OpenGL screensavers on the 7950GT. (I had, just like you, DRI up and working, but I also just got about 1 FPS before I did the above - afterward it was as smooth as silk).

Mind you, I also did install the NVidia linux driver beforehand (of course). I have a strong suspicion that if you do not do this, you won't get acceleration no matter what you do.

If you have a Radeon / ATI card - no idea. With a NVidia card, get the driver, install it, then, once you have booted up with the driver running, see if you set the permissions as I detail above if you get GL accelleration.

As a followup, I did run the euphoria(gl) screensaver and got the same results as I did as a user. It was way too slow.

I looked for an ATI comparable entry in /dev, but didn't see one.

I also tried enemy territory again, and found that I was only getting between 5 and 10 fps, whereas, I was used to getting around 20 fps with slackware 10.2.

At this point, I am wondering if I really am getting 3D rendering. I am thinking about getting the latest ATI driver from ATI and installing it. I find it strange that I cannot find fglrxinfo to verify my driver.

Yeah well... from personal experience, ATI does not seem as committed to Linux as Nvidia is - haven't had the kind of trouble you are having (ever...) with using Nvidia GPUed cards under Linux...

If you cant find fglrxinfo use glxinfo, it comes standard with X11.