Mac Sleep Issues

For years, I've seen a problem with sleep on desktop Macs running OS X (both mine and my mother's). What's odd is that I never saw this problem with laptops going to sleep. I decided that the problem was probably caused by having multiple hard drives in my Mac towers. Although I have a home network, my mother did not have one when her Mac crash-on-wake-from-sleep problem started. The work-around is to (remember to) select Sleep from the Apple menu instead of letting it go to sleep on its own.

Things I tried:

I tried unplugging all USB peripherals except mouse and keyboard (pain in the rear) before sleep.

Remove the SCSI card. (There's a G4 Firmware Update for that problem. On a side note, I got rid of a random kernel panic when I removed the CompUSA USB card, so don't discount removing cards.)

Use different time values for sleep, monitor sleep, and hard drive sleep.

On laptop, make sure that a/c and battery settings are the same in Energy Saver if having wake from sleep problems when changing a/c status.

Delete /var/db/SystemConfiguration/com.apple.PowerManagement.xml as often as needed.

Reset PMU. (How to do this depends on your hardware. Search Apple.)

Of course those didn't work.

Here's the twist, support coming from an unusual direction. My boss' boss also uses a Mac, and often asks me support questions. Yesterday, however, I learned a trick from him. John said he'd been having trouble with sleep until he changed the order of his hard drives. Apparently if OS X is installed on the second drive (and I'll have to think about what that means when I don't have a SCSI ID; maybe he means IDE slave instead of IDE master), he has sleep problems. He figured that out when Leopard wouldn't install on the blank second drive he uses for backups. (With cable select, you can just pull the master.) I think I need to open cases and take a peek to see if I can explain the problems we've had for years!