Xen on 08 September 2011
A faulty PSU is frequently the source of random freezes.Try to underclock and then see if the problem is still there. The old PSU I used in the Pentium 4 I revived for my parents was the source of endless (and usually random) hangs that it experienced - to check, I underclocked (and downvolted) it and it stopped freezing - so I tried out a new Seasonic PSU instead of the old one, now it's overclocked and serves as my HTPC. Butter smooth under any load.
