new discovery:
it seems that the instability is triggered by my IDE DVD drive (LITE-ON DVDRW SOHW-1653S)
SATA, IDE and USB are all controlled by the same chip (nvidia MCP51) so it kinda explains such broad effect.
the machine worked perfectly during 3 weeks when the drive was removed. yesterday it came back and the bug reappeared.
(of course the same drive worked flawlessly in older ubuntu versions and it still works in windows xp)
new discovery:
it seems that the instability is triggered by my IDE DVD drive (LITE-ON DVDRW SOHW-1653S)
SATA, IDE and USB are all controlled by the same chip (nvidia MCP51) so it kinda explains such broad effect.
the machine worked perfectly during 3 weeks when the drive was removed. yesterday it came back and the bug reappeared.
(of course the same drive worked flawlessly in older ubuntu versions and it still works in windows xp)