For about a month my SATA c: drive booting windows XP SP3 is running at only 3.4 to 3.7 megs. It used to run around 50 to 60 megs. I've run every diagnostic I can find on it and they all report that the drive is perfect. It is a WD 320 Gig. I just ran "The Ultimate Boot CD For Windows" to completely bypass the c: drive in the boot process and the drive, when tested by HD Tune without the c: drive's Windows installation in the way, ran at about 90 megs. My backup drive (f an identical WD 320 on SATA, is running fine at the expected 50 - 60 megs. What could have zapped my Windows installation to affect only the c: drive this way and what can I do to put it right without a format and reinstall?
Xp disk drivers got a bug. After 50 read failures it switches to pio mode.
Go to device manager. Then click on the disk controller and choose your drive and right click on it. Choose properties. You should see a mode its in. If its pio uninstall the driver then reboot.
Windows will do its magic and reinstall the drive for you when windows start and your drive would be at full speed again
Thanx for the advice. Tried deleting the driver - no change. Then deleted the drive - no change. What I ended up doing as a last resort (which fixed my problem but created other hassles) was performing a non-destructive reinstall. Windows documentation does not make it clear how to do this but the full nstructions can be found on the Langa List web site. I retained my desktop as well as all of my setttings and the contents of the hard drive but it reverted me to SP2 and I had to perform the upgrade to SP3 and then download and apply all the Windows and Explorer 8 updates. After a few clean-ups and defrags the box is running like a champ again.