Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!ames!ncar!tank!uxc!uxc.cso.uiuc.edu!uxg.cso.uiuc.edu!uxe.cso.uiuc.edu!mcdonald From: mcdonald@uxe.cso.uiuc.edu Newsgroups: comp.sys.ibm.pc Subject: Computer Whine Message-ID: <45900151@uxe.cso.uiuc.edu> Date: 19 Sep 88 14:51:00 GMT Lines: 12 Nf-ID: #N:uxe.cso.uiuc.edu:45900151:000:595 Nf-From: uxe.cso.uiuc.edu!mcdonald Sep 19 09:51:00 1988 I just moved my PS/2 model 80 from my very noisy lab to my nice quiet office. I now notice a very odd thing: When idling at the DOS prompt the system box makes a loud, high pitched whine. When it is actually running a program this ceases. The only explanation I can come up with is that it is drawing lower power from the power supply when idling, and that the supply is a switching one, and hence going to a lower frequency. Then when the power requirement goes up, so does the frequency, above the audible range. I this correct? Why would the MSDOS idle loop draw less power? Doug McDonald