I do noit think you can have SATA and IDE and have them both run at the same time.
if that were the case then SATA would never have taken of seeing as i only know of one manufacturer of SATA optical drives (Plextor) and they are very expensive. there is ABSOLUTELY no reason why you can't use both at the same time. look at my specs, i have 3 hdd's, two of them are SATA and the other is IDE (a.k.a ATA or PATA) and also two optical drives. thats 3 IDE drives and 2 SATA drives so i can assure you it is possible.
don't worry about whatever it said about maximum cpu frequency