Question on screensaver/powersave in KDE F8

[Mike C]

I wonder if anyone can give me any pointers to the following issues:

1) Dell D610 seems to go into screensaver mode far sooner than the kde
screensaver settings should allow. This happens maybe three or four times
and then it settles down and behaves normally after moving the mouse cursor
to get out of the screensaver each time it happens.

http://www.smolts.org/client/show?uuid=pub_d3106a99-890c-4da2-a911-d4f78b5cd818

2) Another Dell this time a desktop Dimension 5150 - if I don't have
firefox running then the screensaver kicks in at the prescribed time, 
and then the monitor goes into powersave at the prescribed timeout.
(There is no power management set in control center - if I set it then
X seems to crash at strange times). If firefox is running then the
screensaver comes in as normal but the monitor fails to enter powersave mode.

http://www.smolts.org/show?UUID=pub_8cb4b211-d13c-441d-ab8a-5bd25f5c3401

Both systems are fully updated F8 and running KDE 3.5 - these "features"
have been present for pretty for quite some time now and I wondered if
anyone has seen anything similar, or who might know a workaround?