Problem with TS-H552U - slow rates

I recently got a new computer with a Samsunb TS-H552U burner which is 16x speed. At first, it was working fine but all of a sudden the read and write rates have gone way done. Before, it would read a full CD using DVD Shrink in about 20 minutes or so. Now, it takes an hour. And, when I burn the image using DVD Decrypter, the write rate is 2.0-2.2 instead of 8x, what I was getting before.

I haven’t changed the kinds of discs I was using and I tried upgrading the firmware. When I first upgraded the firmware, it went back to normal operating speed but now has gone slow again…

Do I need to bring this burner back? Is this a common problem? I am quite new to DVD burners so any help would be great…thanks.

i think you should bring this burner back. İ have got 2 Ts-h552 and i have not got this problem. Take new one, i think.

did you check DMA status?