Extended test (remaining time increase)

I AMM TRYING TO TEST WD RAPTOR DRIVE USING (LIFEGUARD). MY DRIVE PASSED QUICK TEST AND WROTE ZERO ON IT, BUT WHEN I TRY TO RUN EXTENDED TEST, AFTER 20 OR 30MIN ESTIMATED TIME START TO INCRESE. ANYONE KNOW WHY?  

THANK YOU 

The extended test could take several hours, you need to let the test to be completed in order to properly diagnose your drive.

It could be that your drive has encountered a bad area on the media. This results in many sectors requiring several retries. You can see these “slow” sectors using a tool such as MHDD (DOS) or HDDScan (Windows).

Hey, did the extended test even finished or you stopped and try to use one of the software recommended by  fzabkar? Did the drive failed the test?