Confused on HD Tune test

Hey all. I ran HD Tune tests on all my drives in my WHS and noticed something peculiar with my OS drive (WD20EADS). Is this test indicative of poor performance or imminent failure? I ran the error test on it and it scanned for 10hours and all blocks were green/OK and everything is "OK" under the Health tab. I also included a screenshot at the bottom of another WD20EADS in the server (pool data drive).

OS Drive (29% used)


Pool Data Drive (80% used)

That's hard to say, the problem with running HDTune on the boot disk / OS disk is that Windows is usually hitting the drive constantly doing various tasks (page file, DLL loads, file accesses, etc) and you can see results like these. And with WHS it's even worse because WHS does all kinds of 'goofy shit' in the background like moving files around from disk to disk (part of it's file duplication and balancing act) so when you run HDTune you REALLY get a jagged graph.