Poor X performance

I have two LTSP machines. The old machine is redhat 9 machine with
some old ltsp version. The new machine is a ubntu feisty which runs
ltsp 5.

On identical thin client and server hardware, the new ltsp has much
slower video playback.

The users complain because firefox and thunderbird scroll pages in a
jerky manner while the old machine is smooth. Dragging windows around
is about the same speed, if I turn backing store on on the new
machine.

The best quantitative test I've found so far is running glxgears. On
the old machine (X 4.3.99.901 (4.4.0 RC 1) the gears move and it says
around 40fps. On the new machine the (X 7.2.0) the gears don't move
at all, but it claims 80fps. However glx shouldn't be involved, as
other applications should all be 2d.

I've toggled glx, composite (only available on the new X), backing
store, etc, etc.

I'm not sure what else to compare. When I look at the X log for both
machines I don't see any differences of consequence. The client video
card is 3D Rage Pro.

First can someone suggest a better quantitative test for X 2d speed?
If I can measure something, it makes testing so much easier. Next,
can anyone suggest some other bits to toggle?

Otherwise I'm going to have to come to the conclusion that newer ltsp
is plain old heavier weight than the older versions. That would be
sad.
Received on Sun Jan 13 18:56:26 2008