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Since it's not uncommon to keep a running laptop hooked into the 12V system in a vehicle nowadays I figured I'd share this. After all, the less energy your equipment uses the more it helps your overall energy consumption which further translates into better fuel economy.


Hardware: Lenovo Thinkpad X60s (ultra-portable, 12" screen, 3lbs), Intel Duo Core 1.83gHz LV (Centrino 945GM), 1GB DDR2, 40GB SATA (8MB buffer, 5,400 RPM), no optical drive (it's on the expansion dock which I don't use)

Special hardware settings: Bluetooth disabled, on-board ethernet disabled, 2nd CPU core disabled, speed-step & thermals in power-saving mode

OS: Ubuntu Linux 6.10 (Edgy)

Desktop: Gnome

Power saving packages in use: cpufrequtils, laptop-mode, gnome-power-manager, powernow, acpi-support, apm


I have tweaked everything in the OS from dimming the LCD a bit to making the hard disk read-ahead and then idle to forcing the CPU to operate at its minimum speed (1gHz) full-time, etc.

The results under normal usage?

Well, a picture is worth a thousand words so take a look at this, paying special attention to the "Power Information" window at the lower left (it's running purely on its battery starting at the dip at 3:35):

http://www.cyberarmor.net/images/ss/low-power1.png

That's right... running a fully featured OS and a fully mature desktop environment at 1gHz with the display at 1024x768x16, the wifi in use as well as a browser, email client, IM client, MP3/OGG player, SSH terminal, a text editor and a GUI power manager...

All at just 15 watts!

Of course, I could squeeze even more out of it if I went with a desktop environment (DE) that was even slimmer (like XFCE or Enlightenment), but I like having a full-blown DE to work in.

By the way, when all of that stuff is shut down and it's just sitting at an idle desktop it only draws about 12W. When the screen turns off after 10 minutes of idle time it drops to 9W. When it suspends after 20 minutes it goes to 6W.

Late last year I got a new desktop (that I have yet to migrate all the data :( ). Really wished I got a laptop to save energy and increase mobility.

Late last year I got a new desktop (that I have yet to migrate all the data :( ). Really wished I got a laptop to save energy and increase mobility.

Laptops are the only way to go! I did away with our desktop 2 years ago.
My wife and I have our own WIRELESS laptops, its great having everything anywhere in the house! And they do take less power..
Gary

One thought is set the laptop on top of the treadmill at home (not litterally). I could walk or slowlly job while surfing. Definitely a time saver and fitness aid, but a tossup on energy saver.

what application are you running to view the power useage?

FYI, moved thread to general.

what application are you running to view the power useage?

That's the gnome-power-manager, which is part of the Gnome desktop.

Of course, I could squeeze even more out of it if I went with a desktop environment (DE) that was even slimmer (like XFCE or Enlightenment), but I like having a full-blown DE to work in.

Try it. I'm curious about the results. I don't think you'll see much of a difference, especially since suspend only drops ~3W. A slight reduction in memory and/or processing load shouldn't reduce power consumption on an already under clocked lappy iirc, but I could be wrong.

Try it. I'm curious about the results. I don't think you'll see much of a difference, especially since suspend only drops ~3W. A slight reduction in memory and/or processing load shouldn't reduce power consumption on an already under clocked lappy iirc, but I could be wrong.
I have already tried it, with positive (although small) results.

The power draw of KDE vs. Gnome is large, about 1.25W-2W, depending on what you are doing. This negates running KDE on anything where power consumption is a concern.

The power draw difference between Gnome and XFCE is much smaller as Gnome is already pretty efficient, about 0.2W. This is why I say that I could indeed squeeze even lower wattage out but that it's not worth it to me.

I could find no appreciable difference between XFCE and Enlightenment. It seems that not pre-drawing anything on the screen (like application menus and task bars) balances out running a lot of transparencies.

It seems that not pre-drawing anything on the screen (like application menus and task bars) balances out running a lot of transparencies.

Fascinating, thanks for the info!

Thought about running in a text-only environment on the
VTYs by default, and only firing up X when you need it?
.
_H*

@hobbit:

Yes, I thought about that, but 99% of the time my laptop is fired up for something that runs smoother in a GUI.