Philips DVD+-RW DVD 8631 burning problem

so i’ve got a philips DVD±RW DVD 8631, and it was working great until recently, when it starting burning much slower (1x-1.8x, instead of 7x-8x), and when i try to play audio at the same time it plays very choppy. i’m using the same media as before, i thought maybe installing an internal hard drive on the same IDE cable might have messed it up, but i removed it and still have the same problem. any idea if there’s something wrong, or if the drive just went bad (its about 2 years old)? is there any other information that would be helpful?