800 MB discs must be overburned if your Aopen CRW4852 supports overburning. Use the following procedure with Nero:
90 and 99 minute discs are nonstandard lengths, and will theoretically hold 791 MB and 870 MB of data respectively. They will always be recognized as 80 minute discs because this is the maximum length allowed by the standards. A disc over 700 MB (80 minutes) must use Nero overburn settings to allow it to be burned. Use the following settings for a data disk:
Don't use the Nero Wizard. It will not allow overburning as it defaults to Track-At-Once. If it is active, close it.
Multisession | No Multisession must be checked
ISO | Check Mode 1 and Joliet
Burn | Check Write and Finalize CD (No further writing possible). Write method must be Disk-At-Once.
In the main menu, File | Preferences | Expert Settings check "Enable overburn disk-at-once burning". If you are using a 90 minute disc, you can set the Maximum CD length to 90 minutes 0 seconds 0 frm. Hit Apply, then OK. If you are using a 650 or 700 MB data disc, use the overburn capacity test in Nero CD Speed to estimate the maximum overburn capacity. If for some reason the test doesn't work, create an audio overburn test disc to determine the overburn capacity. Use the determined overburn capacity in Expert Settings.
The Red and Yellow marker settings in File | Preferences | General Settings have no effect on burning or overburning. They are there just as a visual aid.
These settings should allow you to attempt an overburn if your recorder and the media support it.
To create an audio overburn test disc:
Most 80 minute CDR's can overburn from about 81.5 to 82.5 minutes or so. If you can spare a disc for testing, record an audio disc with extended length source material beyond the expected overburn capacity. When the burn eventually fails, the point at which it fails will be the overburn capacity of that disc. The audio disc will still be playable, and the total minutes of the disc is the total overburn capacity.