I experienced a big problem in a similar setup (but it might have been due to combination of two drives of different manufacturers or ATA33/ATA66 mixing.
I\'ve got one Fujitsu ATA33, one Seagate ATA66 configured as ATA33, one CD-ROM (Goldstar ATAPI from 1996)and one ZIP, my motherboard supports ATA33. First I tried to connect the two HDs on the primary port, and the CD-ROM/ZIP on the secondary. It worked fine until I tried to switch the DMA on the Seagate. Afterwards, when copying files from Fujitsu onto the Seagate, the letter one would get hooked and worked endlessly in the speed of \"4 Hz\" (that\'s how fast the HD-access LED blinked). Than I connected the two HD\'s as Masters on each port, the other drives being Slaves (CD-Rom partnering the Seagate). The result was the same, although the problem did not appear always. I found out, that if CD-Rom was working or had CD in it, the problem was there 100%. So I swapped the Goldstar for newer TEAC (1998) and it seems to work. I just must not let the CD-Rom work while I am using the Seagate for critical work (Audio, Gigastudio) because it slows down the HD significantly.
So I do not know what the best solution would be for you, I would say you have to try out.
For me I just want one CDRW only in the audio system. I see the advantage of 2nd CDR because of its fast-transfer-data and I also see the disadvantage of it which is more complexity hardware in my system (IDE cable, audio cable, power supply, IDE resource, mechanical). How many percents of your PC time to use the CDR? My opinion is never put un-necessory stuffs (software and hardware)in my audio-system, due to keep all best taking performance and the quality as well in my audio systems (less devices, less used power, less noises, less troubles, more resources available, etc).
And I see someone here even want to dedicate a PC, just does the Sampler work only!
Just a thought! don\'t take my words for it!
This setup gives me 14+ Megs /sec on the Maxtor. When I took out the CDROM, I was getting 30 Megs /sec. This convinced me that if I don\'t have the CDROM on a separate controller (such as SCSI), don\'t bother putting a CDROM drive. I don\'t have CDROM drive anymore... till I get a SCSI CDROM or something.