Periodic, temporary screen weirdness. (FC1 / Matrox Millenium)

[Scott Merritt]

After using the machine for a while, everything will be fine and 
*boom*.  It appears to change the resolution and then I get thrown back 
into my X session but it's all screwed up.  There's some funky lines on 
the top half of the display and everything seems to be frozen.  I can 
sort of see an outline of the windows open, but I can't do anything.  If 
I hit the keyboard or use the mouse while in this state, it will change 
things around by the time it comes back.

But, every time it does this I get to sit there for a good 10 seconds 
before it returns, all back to normal.  It seems to do this about every 
10 minutes or so.

I thought, maybe it was the screen saver, so I changed it to something 
else.  Then I turned it off.  Although I'm actively using the machine, 
one wouldn't think that to be the problem.  I've tried changing the 
resolution, refreshrate, color depth, etc.  I've kept up to date with my 
packages, so I'm not sure what's going on.  I don't have any fancy 
hardware going on.

Everything else works great, but this does get pretty annoying.  Any ideas?

FC1
kernel 2.4.22-1.2174
Pentium II - 266
Matrox Millenium