Hello,
You are right, news Hds and others devices ask a lot of Watts...
My solution, but not the only I hope, is to use a PC power supply for all devices. However to avoid any problem of mainboard alimentation, I just kept the original PSU. Thus, now I have two PSU: one amiga for the mainboard and one PC PSU for all HD and what you want. It is not very beautiful but it's powerful!!!
David
