Strange jump in latency #'s 20000 => 300,000+

I tried running latency test for kicks on my really old machine last night... it's been acting a bit weird.
I ran latency test for around 20 minutes with a combination of a bunch of glxgear windows, reloading firefox webpages and running the internet speed test over and over.

Just launching the first xterm made the latency jump up into the 300,000's after boot up. I was able to bump that up to around 390,000 just by abusing the computer a bit more.

This hardware has been working for 3 years now, and the previous jitter value entered into stepconf was around 20,000.
I ran the test overnight the last time I ran this test in order to arrive at the 20,000 number.

I've noticed a message on boot up recently about not being able to mount the harddrive, and that a check is needed. I would imagine that any operations having difficulty pulling data from the harddrive would negatively impact the timing test.. but even a simple xterm launch caused havoc.

Anyone else notice something like this?

A failing hard drive system is a known source of latency issues...

thanks, looks like its time to yank the data off this pc and toss in a new HD