Performance degrades after using for a while

[Ian Pilcher]

So this is driving me nuts, and I don't have a clue how to figure out
what's going on.

Briefly, X1650 Pro (1002:71c1) driving 2 DVI-connected 1680x1050 LCDs on
Fedora 14.  X performance is good when it first starts; glxgears reports
around 59.9 FPS with vsync and 1211 FPS without vsync.  After a variable
period of time, however, X performance becomes noticeably sluggish.
konsole sessions feel like I'm ssh'ed to the other side of the planet
and glxgears can only manage around 31 FPS with vsync and 190 without.

Restarting X "fixes" the problem temporarily.

I have been unable to pin down what causes the change in performance.
There's nothing in the X.org log, /var/log/messages, or dmesg that
points to a change.  /proc/interrupts shows that the card is still
generating 60 interrupts per second when I'm not doing anything.

Can anyone make any suggestions on how I can debug this?

(If it gives anyone any ideas, it's probably worth noting that I did not
have this problem with the driver version in Fedora 13.)

Thanks!

-- 
========================================================================
Ian Pilcher                                         arequipeno at gmail.com
========================================================================