It has subkeys like 0000, 0001, 0002, etc. Normally 0001 is the primary IDE channel, 0002 the secondary, but other numbers can occur under certain circumstances. Check the DriverDesc value to see which one it is.
Delete MasterIdDataChecksum or SlaveIdDataChecksum, depending on whether the device in question is attached as master or slave. The drive DMA capabilities will be redetected.
when i encounter this type of slow hard disk performance i delte both MasterIdDataChecksum or SlaveIdDataChecksum and after that i restart the pc and every think is fine