YUDEN000 T02 is 8x, not 16x
If we could get the MID from those Ridata discs, that would be nice to know, although Evilboy may well be right, as Ridata aren't anywhere near as good as Verbies and TYs.
Download CD-DVD Speed (or find it in the Nero Toolkit), pop one of the Ridata discs in, and go to the "Disc Info" tab. There you should see the MID - if you could post that, it'd be great
BTW. welcome to the forum