This article is from the Amiga CD32 FAQ, by Stuart Tomlinson with numerous contributions by others.
A: They are indeed power related, but it's voltage, not wattage.
Garry Cardinal <cardinal@ARC.AB.CA> wrote:
"My SX-1 enhanced CD-32 began hanging when I added an IDE drive to it. When using the hd the system would suddenly freeze. I had a 2Mb SIMM installed, going to another SIMM or hard disk did not correct the problem. This was all independent of FMV card presence.
My SX-1's strange behaviour persisted until I bypassed the connections between the CD-32 power switch and the SX-1."
I soldered a standard PC power supply female molex connector to the power switch on the CD-32 (switched side) and soldered a standard male molex connector to the SX-1 +12 and +5 power supply distribution system as close as possible to the 2.5" hard disk connector and ram socket.
(Of course, observe antistatic precautions. Those faint of heart, take this text to a qualified service provider for the appropriate action. )
When I was done, my problems disappeared.
CD-32 SX-1 (with extra switch for memory test jumper plugging DB25 hole) 20Mb Connor 2.5 4Mb 32 bit simm FMV card A500 Power Supply"