First, let me describe a bit the optical drives I use.
I have an ASUS CDS-500 as a reader, the drive is 3 1/2 years old and has been used extensively but has proven to be extremely reliable and good at reading any disc except really destroyed ones. I was very satisfied with this reader, so two months ago I bought another ASUS drive, the CRW-4816A despite negative reviews on CDRLabs and other sites.
The first burns I did with my new writer (at low speeds, 16X 24X and 32X) were succesful as I was using good quality media (TDK d-view mainly). I tested almost all of the burned discs first in the burner and then in the CDS-500 to see if there are any differences, and none of them showed any errors on CDSpeed's Disk Quality Check.
But as I started using various cheaper media (Ritek, Prodisc, MMM&M, Gigastorage, Fornet Int'l and others, burned at 32X at most) not all the burns are 100% succesful. And by that I don't mean coasters, but some of the discs show some C2 errors, not many (a few thousands at most), usually towards the outer tracks, and only when tested at 48X reading speed with the CRW4816.
There are no errors when I test the same discs in my CDS-500, even at maximum speed (50X), and there are no errors if I test the discs in the CRW4816 at 40X reading speed. In addidion, the CRW4816 is somewhat inconsistent about the errors it reports, as the results are very different each time I run the test. A particular disc may show 5000 errors at one test only to have 0 errors if I test again or vice versa...
I wonder if the conclusion of the reviews stating that ASUS CRW-4816A has poor writing quality is based only on read tests conducted on the same drive. If that is true, could this drive be only a mediocre (or really bad) reader and not a bad burner, or is it a combination of both? Did someone conducted a C1/C2 test on discs written by the CRW4816 using another drive (Lite-On?) for reading?