I have a Linux (RHEL5) machine here at work that has started "hiccupping".

Basically, it works fine for about 28-29 seconds, then … pauses for about 4 seconds, then repeats. When I say "pause", I mean that the machine does not produce any output or seemingly accept any input. I know that other times I've seen these sorts of symptoms, input during the paused time would seem to be played back after the pause, but that does not seem to be the case here. (I could be wrong, though.)

There is nothing in any logs or in dmesg. I have a vague suspicion that it might be related to the nvidia kernel module, but I don't really have any good basis for that suspicion.

Since the pause seemingly affects every function of the machine, using top, or any other real-time monitor, proves ineffective, since I'm only interested in the output when it's not able to generate any.

I'm kind of out of ideas as to where to look. Anyone else have any?