Different drives perform differently with different media. I heavily suspect that my LiteON could burn the Datastream 48x CD-Rs at 52x.
Why make 52x CD-Rs if 48x CD-Rs can be burned at 52x??
there are 2 likely answers:
1) not all drives can "overclock" CD-Rs (burn them faster then their certified speed), and each drive uses different ways to judge the maximum possible speed that media can be burned at, so even if some drives can burn it at 52x, they might mark it as 48x to ensure compatiblity.
2) (This one I believe to be the most likely) It costs significantly less to set a machine up once, and make 2 billion CD-Rs that are 52x and sell half of them as 48x, then it would to set the machine up twice, and make 1 billion CD-Rs for 48x and another billion for 52x. I have no idea how many CD-Rs are generally produced on a single run, however I like the sound of 1 billion
Punch Cards -> Paper Tape -> Tape Drive -> 8" Floppy Diskette -> 5 1/4" Floppy Diskette -> 3 1/2" "Flippy" Diskette -> CD-R -> DVD±R -> BD-R
The Progression of Computer Media