Super User is a question and answer site for computer enthusiasts and power users. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Earlier I inserted a SATA drive into a simple one drive backplane I have. After a "detect hardware changes" the drive appeared, and worked correctly. Later, I removed it.

Since that time, my primary SATA drive, a Western Digital Caviar Black 640GB, which was never disconnected, is extremely slow, on the order of 4.0MB/second maximum transfer rate.

The first thing I considered is that the drive might be failing, but it passes the DataLifeguard Quick Test and Windows chkdsk. While this cannot rule out a hardware problem, it indicates against it.

Can my insertion and removal of another SATA drive have reset the connection into some very slow compatibility mode? How do I fix it? If that is not the problem, what else could cause this?

share|improve this question
up vote 3 down vote accepted

Sure enough, the controller channel had fallen back to PIO from Ultra DMA 5.

The solution was:

  1. Find the sub-key for the controller channel within:

  2. Delete MasterIdDataChecksum and SlaveIdDataChecksum

  3. Reboot

share|improve this answer
+1 For the smart explanation and for sharing the solution! – Alain Pannetier Jun 4 '11 at 8:33

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .