Power Management & Best IT Practices at Harvard

Power Management

CRT monitors can use two-thirds of the total energy of the computer system,

so it's very important to enable power management for at least your monitor. The software provided below will automatically set your monitor to go to sleep after a period of time you designate. FAS-CERP recommends 10-20 minutes. Monitor Power Management

Remember: Screensavers don't save energy. In fact, they can keep your computer in an active state, thereby preventing it from going into an energy-saving sleep mode. If you find that your system doesn't go to sleep after you've enabled power management, try disabling your screensaver. Screensavers are technologically obsolete and actually do little or nothing to prolong the life of your display. If you like the aesthetic appeal of your screensaver, try replacing it with a nice desktop image or wallpaper.

We also recommend that you enable power management to put your CPU to sleep after 10-20 minutes of inactivity.

Mac users: Go to System Preferences/Energy Saver.

PC Users: Go to Control Panel/Power Options. (We have heard a few complaints about computers crashing or work being lost in standby mode. We, therefore, suggest using the hibernate mode. Unlike standby, hibernate saves your active files before going to sleep.)

For more detailed instructions how to manually set power management for your monitor and CPU, click here

Best IT Practices at Harvard

Physics Department

Physics IT Services have taken a number of steps to reduce energy consumption of electrical equipment in their department.
One of those steps consisted of removing about 65 desktop PCs (PC and Mac) by moving 1st and 2nd year grad students to thin clients (terminals). These terminals all connect to a Linux server and behave as though they were a regular Linux box when someone logs in.

Each terminals (a Wyse S30) consumes about 5.6 watts max (as opposed to 100-200 watts for a PC - without a monitor). The terminals are tied to Viewsonic flat panels LCDs (TCO'99 and ENERGY STAR compliant) which consume about 42 watts when in full operation. When the monitor and terminal are not in use and go into low power modes, it is estimated that they consume around 6 to 10 watts (possibly even less).

The server consumes between 400-700 watts (depending on the current load) or the equivalent of a half dozen desktop PCs. While the server stays always on, it has allowed Physics to reduce the number of desktop PCs by 65!

  • 65 terminals = approx. 3100 watts total (~ 47.6 watts max. for each  with monitor - probably avg. 40 w/hr)
  • 1 terminal server = approx. 400-700 watts max. 4 public PC terminals (2 eMacs, 2 PCs) = approx. 700 total watts if  all in use - approx. 90 watts or less total when sleeping

The 4 public PCs are in common areas for graduate student who  absolutely need a Windows or Mac for a specific task. These machines  spend more time in sleep mode than operation, and are rarely all on  at the same time. Additionally, the eMacs will turn themselves off  almost completely between 11pm and 7am, consuming only enough power  for the timer to restart them in the morning.

Says Maggie McFee, Systems Administrator in Jefferson: "Most people don't realize that Macs can do this - you can set a shut off and restart time in System Preferences. We'll eventually replace the CRT eMacs with LCD iMacs which will reduce total consumption further. My conservative "guesstimate" is that [by switching to terminals] we've reduced our consumption by about 6,500 watt/hr during peak (although, my gut feeling is that it's actually a bit higher - probably around 8,000 w/hr. This also reduces the amount of heat released into the building."