This is the solution worked for me when my IDE hardisk write/read speed suddenlydropped under 1mb/s
NOTE - be careful - it's recommended you backup your Registry BEFORE you do this.
Start
- Run - type regedit, OK, choose Edit - Find - type
masteriddatachecksum - delete all the entities found, on the right, that
have that - press F3 to search again (there is usually more than one);
do the same for slaveiddatachecksum; exit regedit - reboot - your
drives should be their max DMA, or the mboard's max DMA if that's less.
Extract from
http://www.computing.net/answers/hardware/ide-ataatapi-controllers-secondary-ide-cha/66781.html
