3520 and 3550 in multiple setup?

Can I use these 2 different burners to do simultaneous multiple burns using Nero 6.6.0.6, Windows xp, athlon 1.8ghz, 1 gig mem or do I need the exact same burners and firmware?

Yes you can

Yes it’s possible
you dont even need two of the same drives (they are not working together, your system is just using both at the same time)

I use the NEC 3540 and Benq 1640 simultaneous.

The most important thing is that your harddrive is fast enough.
If used together, I burn @ 8x max, and both drives are set a master on their own IDE channel. My HD is a SATA maxtor 250 gig.

Has anyone had success dual burning at 12x using PATA harddrives?

I think it isn’t depends from the type of your HDD

you’re right, thats why I have both drives set solo on different IDE channels also :slight_smile: