It the other way, of course : they might have imperfect C2 if there were more errors.
According to the EAC graphs for the Asus (
http://www.cdr-info.com/Sections/Art...D%2DRW&index=2), published at CDRinfo, the green part never crossed the 8th line, that is less than 3000 errors per second. Nero CD Speed graph shows less that 3500 errors, although I don't know if they are errors per second, in samples or bytes.
For Sony (
http://www.cdr-info.com/Sections/Art...p+Vol1&index=3), the CD Speed graph is similar : less than 3500 errors (per second ?).
The error rate can grow up to 88200 per second in EAC graphs, and should go up to 176400 in Nero CD speed (C2 errors per second, 4 bytes per sample).
Now look at the sony DDU1621 behaviour :
C2 accuracy on random errors, in %, of the Sony DDU1621 firmware S1.6 DVD ROM drive, versus error rate in mono samples
This was obtained in the tests described here :
http://perso.numericable.fr/laguill2/dae/dae.htm
You can see that the C2 accuracy of this drive is OK (99.3 %, see the
C2 accuracy analysis part ) until about 25000 errors per second in mono samples, and then collapses completely, until missing nearly every other error at 88200 mono samples per second.
Those high error rate can occur as soon as one single scratch appear on the CD, if it it parallel to the groove (making the CD skip).