Hi and Welcome!
could you please specify exactly? I am asking since I can't find M4785 on Asus website.
and a new Promise Ultra133 IDE controller. Neither of his two Sony Optiarc will work correctly. They are very SLOW and they error on any CDs he tries to write. Why are they so slow? He has the 80 pin cables, everything.
Promise Ultra 133 controllers were not designed to support optical drives.
At least the M4A785-M has an IDE connector onboard, so you should connect your drive there and see if that works.
Additionally, please check if the jumpers are set correctly. With two drives on one cable, the drive on the end of the cable (black connector) must be set to Master, the other one to Slave position.