PIO mode

For the past few months my computer has been occasionally switching my HDD from UDMA 6 to PIO mode. This is rather annoying as the fix is to set it to PIO mode only, restart, then set it to DMA when available, and, if any of you have ever had this happen, you know the shut down and start up times when your drive is in PIO mode are like 10 times normal. I've tried switching the sata port the drive is attached to and the sata cable is definitely in place and not loose.

Any ideas what may be causing this? Should I be pricing new drives?

http://winhlp.com/node/10

PIO mode is enabled by default in the following situations:
...
For repeated DMA errors. Windows XP will turn off DMA mode for a device after encountering certain errors during data transfer operations. If more that six DMA transfer timeouts occur, Windows will turn off DMA and use only PIO mode on that device.

In this case, the user cannot turn on DMA for this device. The only option for the user who wants to enable DMA mode is to uninstall and reinstall the device.

Windows XP downgrades the Ultra DMA transfer mode after receiving more than six CRC errors. Whenever possible, the operating system will step down one UDMA mode at a time (from UDMA mode 4 to UDMA mode 3, and so on).

http://winhlp.com/node/10

PIO mode is enabled by default in the following situations:
...
For repeated DMA errors. Windows XP will turn off DMA mode for a device after encountering certain errors during data transfer operations. If more that six DMA transfer timeouts occur, Windows will turn off DMA and use only PIO mode on that device.

In this case, the user cannot turn on DMA for this device. The only option for the user who wants to enable DMA mode is to uninstall and reinstall the device.

Windows XP downgrades the Ultra DMA transfer mode after receiving more than six CRC errors. Whenever possible, the operating system will step down one UDMA mode at a time (from UDMA mode 4 to UDMA mode 3, and so on).

--Anna--

I am aware of all this, however, I'm wondering if there's a problem with my hdd and if that means it's on its way out. Interestingly, my computer changed from mode 6 before I put it in standby last night to mode 4 when I started it back up today.

Also, you can enable DMA again without uninstalling the device by following the procedure I covered in my OP.

If your using a sata1 drive with a sata 2 controller try putting a jumper on the 150mbps pins on the back of the drive, hopefully you have that jumper but i dont think all drives do. It can also happen if you overclock too high, I think there's other things that can cause it, but that fixed it for me.

Back up all of your stuff! In 2001 I had a 20GB hard drive that would always switch into PIO mode. The problem kept getting worse until it died 2 months later.