From the CD writing tests:
The result is very good, although we note that the burn was slowed down near the end of the disc.
there is nothing wrong here - the drive reaches its rated maximum speed (48x) rather early and keeps it until the end of the disc. I would not call this a slowdown.
What's also interesting: According to the sticker on the drive, 2,5A @12V are required. This power requirement makes this drive not recommendable if installation in external enclosures is intended (their PSUs normally reach 2A @12V if the weather is nice, the girls are pretty and the beer is cold).