Sounds like it's over-heating. Have you cleaned it lately or moved something that changes the air flow? _________________________________ i'm EMAILING FOR THE GREATER GOOD Join me http://im.live.com/Messenger/IM/Home/?source=EML_WLHM_GreaterGood ________________________________ > Date: Mon, 28 Sep 2009 21:50:31 +0200 > From: ronaldbs at gmail.com > To: g4 at listserver.themacintoshguy.com > Subject: [G4] sleepy MDD 1ghz > > can anyone enlighten me re the following phenomenon: my MDD has begun to go into sleep mode every 10-20 minutes - when sleep mode is not configued in the control panels. What happens, whether i am working or not is that the fans suddenly seem to kick in and then the MDD takes a nap until i hit the keyboard. > > thanks > > ronald