I've had some computer behavior that I don't understand.
Perhaps someone can explain what I'm seeing.
Over the past year, I've had two desktop computer systems, both 64 bit windows.
The first system had a WD 300Gbyte Velociraptor disk. It also had a defective motherboard that I replaced. But after the motherboard replacement, the system would go into 30 second long disk delays in Windows 7, several times a day, generally related to a context change like switching windows. Most processes in windows would stop, and there would be 30 seconds of furious disk activity, where I could move the cursor around on the screen, but nothing else would happen. After 30 seconds or so, the system would recover and be fine.
I tested everything, but could never find any hardware issues or any indication in the system logs as to what the system was doing in these periods of disk activity.
Eventually, I backed up the Velociraptor disk (which was my C disk), and replaced it with another hard drive.
The problem went away.
So then I put together a similar, second system. I thought, well, maybe the problem with the first system was not the Velociraptor disk, but related to some Windows problem that Microsoft had fixed with an update. I did a long re-format of the Velociraptor drive, and did an extensive set of test on it --- all tests passed, and the SMART values were all OK. So, I figured the drive was OK, and I put it in the second computer system (all other hardware parts different from the first), and set up the system.
At first it was OK, but after a few weeks, it again started showing the 30-second disk delays, when switching contexts. I defragged the disk, I tested it --- nothing showed up in the tests, nothing helped. Note that the 300 Gig disk was only half full --- I was careful to move all my personal stuff to other drives on the system.
So now I've backed up the second system and re-installed it on a new C drive. The problem has again gone away, and has been gone for a week now.
How can a hard drive that tests OK cause delay problems with Win 7? Because that's what I seem to be seeing. Do you think it would be worth sending the Velociraptor back to Western Digital for testing?