I have PowerMac 6500 with Crescendo/L2 G3 OS 8.6. Sleep Mode. Monitor goes to Sleep mode OK. I feel the processor and disk do not go to Sleep Mode. You can't hear the Disk spin down because the computer is so quiet normally when its working. Is there any way to be sure? I may have already posted, but I can't remember where. I've been over the entire web without any answer. In the Control Panel I selected only the Computer and Disk Settings (Not the Monitor) I set it to sleep at a certain time. It never goes to sleep that way. If I also set the Monitor then it does go to sleep but I think only the Monitor. I know it was asleep because the little Power Indicator goes on and off and the Monitor takes a while to come up to full brightness. I don't feel the Computer or Disk ever were in sleep because it should take longer to awake if everything was asleep. The Manual is very unclear about Sleep Mode, just a couple of unclear mentions.