Periodic Fedora 9 system hangs with jumpy mouse

[Alan Cox]

> When the system hangs, the mouse cursor will continue to move, but it
> is very jumpy
> and sluggish.  But otherwise the system is completely unresponsive
> (not just slow).

That sounds like it suddenly ran out of memory.

Try

	echo "2" >/proc/sys/vm/overcommit_memory
	echo "80" >/proc/sys/vm/overcommit_ration

and see if instead you suddenly see lots of out of memory errors and
applications going away

> ctrl+alt sequences. The only thing I can do is to do a hard power-off
> and reboot.

Does anything make /var/log/messages ?

> This system is a Dell Optiplex GX270 (4-5 yrs old) with a Pentium 4 3GHz cpu
> with hyperthreading enabled, 1 MB ram.  I am using LVM and LUKS encryption
> on the swap and /home.

1MB or 1GB. 1MB might be a bit slow so I suspect the latter ;)

I wonder if LUKS + swap might be the first suspect

> The only hardware change in the system was replacing my old PCI graphics
> card (Matrox Millenium II) with a brand new ATI Stealth X1050 AGP.  This was
> necessary because the F9 graphical install was unusable; as the old card only
> had VGA output and the installer's X11 could not properly auto-detect the LCD
> widescreen monitor and was trying to drive it at too high a frequency.  I needed
> to have DVI output for the F9 graphical install to work; so I had to get a new
> video card.

Which video driver are you using ?

Alan