How much energy does my old laptop use?

December 26, 2008 11:24 AM

How much energy does my old laptop use?

I have an old Compaq Presario 17XL460 laptop. It's stock with no improvements.

I need a place to set up some software development services (source code control, issue management, etc.) to be available all the time. They would run on a Linux distro. I have this old laptop sitting around doing nothing, but I won't necessarily use it if it's going to suck down a lot of energy. In fact, if it's a large amount of energy, I'd look into a hosted source code solution.

How much energy would a laptop this old use by being on all the time? How does this compare to what today's desktops and notebooks use?

posted by clearlynuts to computers & internet (4 comments total)

Let's see. Its battery is 4000mAh, 14.8V, which is about 60 Wh. If that lasts 2 hours, it's using 30W. It probably lasts longer than that (when new), but let's say that cancels out the inefficiency in the power supply, so:

It probably uses around 30W. That's not very much. It definitely uses less than 60W, which is quite low for a desktop machine or a server.
posted by aubilenon at 11:35 AM on December 26, 2008

You could grab a cheap power metre (like the Kill-a-Watt) if you want an exact answer.

Consider that most 'low-power' desktop & server CPUs (other than the extreme low-power options like the VIA C3 or the Atom) are rated at 50+ W for the CPU alone. Your laptop will be a model of energy efficiency by comparison, especially if you close the lid, switching off the LCD.
posted by rodgerd at 12:15 PM on December 26, 2008

Buy a cheap power meter that can do Kilowatt-Hours, like the aforementioned Kill-a-watt. After you run it for a few hours, look up the figures. Some of them will even tell you the cost of running it if you program in the cost of electricity in your area. If this is running something simple like a revision server, etc it shouldn't take much, as long as you make sure that the power saving settings (like spinning down drives, displays, etc) are enabled.
posted by baggers at 12:31 PM on December 26, 2008

rodgerd is right on: most of the power will probably be used by the lcd, so if you can turn it off either manually or by shutting the lid and just ssh in you will cut back a huge amount of power use. With Linux, just turning the display off entirely as a default booting mode is trivial.
posted by idiopath at 1:57 PM on December 26, 2008