I have this situation on a couple of my Macs, one a PowerMac G5 (DP 2.0 GHz, 5 Gig RAM, 250 Meg/500 Meg HD), the other a Mac Mini (Core Duo 1.6, 1 Gig RAM, 60 Gig HD), the PowerMac running Leopard and the Mini running snow leopard.
Both machines are set to sleep the display after about ten...