testing hardware - use what software ?

[David Timms]

I have a PC that is failing intermittently. What are the best choice for 
attempting to pinpoint a hardware fault - in terms of either fedora 
packaged or other open sourcesoftware ?

Perhaps there is something that can both perform one of and 'to death' 
tests of various PC components, and components in combination, and also 
provide peak workload for all subsystems at once, in an attempt to 
generate a slow to occur failure.

I know about memtest, and read-only disk tests from fsck. Any others ?

DaveT.