3. Nero CD Speed
Testing C2 error information - Page 3
Nero CD Speed
The Nero CD Speed software compares on-the-fly, byte-to-byte, and the extracted data of the test disc with an image. The software measures three types of C2 errors:
- C2 Errors is the amount of errors reported by the drive.
- Compare Errors are the differences between the original image file and the data on the test disc.
- C2 Missed are present when the drive did not report an error while there
was a difference between the image file and the test disc (i.e. comparison
bit to bit).
According to how many C2 errors are reported/missed each drive gets a % accuracy score. The CDSpeed test also includes a "reverse" switch for some drives (usually with RICOH chipsets), as also found with the EAC analyser software.
Below is the CDSpeed graph of the SONY CRX-220E1. As we have seen earlier the drive got 100% score with EAC and also gets 100% with CDSpeed!
Below is another example of the EAC and CDSpeed similar scores. With EAC the drive got a 99.4%, while with CDSpeed 97.4%.
Lastly, with some drives the EAC and CDSpeed results will not agree. EAC gives a 67% score, while CDSpeed 26.38%.
A possible explanation is that when so many sync error occur its nearly impossible to calculate with accuracy the C2 error report information. Remember that if we need drives with at least 99% accuracy to be used for perfect DAE extraction.
Note: In most cases the EAC and CDSpeed C2 percentages would be similar. Both are linear (that means x per 100 c2 errors are not reported). However, due to different calculation method, there have been cases, where a drive got much different percentages in CDSpeed and EAC tests. Never less, a drive should have more than 95% score to be used for checking the writing quality of a disc...