sub mesa said:
Download HDTune and do a benchmark. If your drive never reaches higher than 16.6MB/s, then you have a PIO issue.
Also check the health tab of HDtune; it could be that you have bad sectors or cabling issues.
Cable issues would identify as UDMA CRC Error Count in your SMART Data. Look at last column called "data"; these list the raw values you should be looking at.
Tx for the reply. I'm looking in