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In theory, switching from the ondemand governor to conservative should save battery life on laptops.

However, I don't think I've ever seen any tests done to verify this or show how significant a saving can be made.

Can anyone find a source where such tests have been done?

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You could conduct this test yourself, but I believe the most power cost come from the Monitor. – warl0ck Oct 4 '12 at 23:34
I suspect the same but I haven't seen actual figures before. A lot of sites recommend altering the CPU governor to get more laptop battery life, and my theory is that this is not gonna save you anything significant :) – trr Oct 5 '12 at 0:46

Here are some tests done by the folks @ IBM:

cpufreq tuning results

They're not specifically testing battery life but should give you an idea about ondemand - versus - conservative power consumption.

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Thanks for that interesting link. It looks like ondemand and conservative are identical at 0% load and from 50% load to 100% load, while loads from 1% to 49% will benefit by up to ~30 Watts out of an insane ~380 Watts. This is one seriously power-hungry system with something like 10 times the power usage of a modern laptop. – trr Oct 5 '12 at 0:44

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