well before now i had 2 scenarios,

1 - computer freezes, have to pressed power button to bring up shutdown screen then hit cancel to resume working.

2 - computer freezes with mouse still movable, nothing works except holding the power button down to power off.

scenario 1 happened after 10 minutes after booting, and 10 minutes thereafter.

scenario 2 happened EVERY TIME i booted the computer after about a half hour of use.

Now after editing xorg, adding uxa, saving,rebooting, freezing, removing uxa, rebooting... suddenly everything is ok. the freezes definately were NOT random for me, and i should have had them happen by now, ive been using the pc for 3 hours now without freezing.