Can you provide a list of drivers you have loaded in C:\Windows\System\IoSubsys directory?
Do you have the latest drivers for your IDE controller? What controller chip do you have? Intel, VIA, SIS,etc?
Have you used the CTRL-ALT-DEl key, and close all programs running in the background, except for Systray and Explorer, and then try and format the CDRW media? Does it still take up so much CPU in this fashion?
I'm using Win98(original) and I've tried Nero 126.96.36.199 and 188.8.131.52 and InCD 3.24.3. I even tried an older version of InCD but it wouldn't recognize my drive. I forgot to mention that Incd wouldn't even let me uninstall until I did a ctrl-alt-del and killed it. It gave me an error about it accessing the drive or something even though it wasn't.