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0e1f616
(Get the code!)
I did some power tests on my Samsung N220 Plus (atom n450 based netbook) using phoronix test suite battery power usage test.
The details are published here: http://
In summary, the results are this (average power use in mW):
10.10 7660.37
11.04 unity pcie_aspm=force 8263.59
11.04 classic (no effects) pcie_aspm=force 8156.98
11.04 unity 8795.90
11.04 classic (no effects) 8194.49
Especially notice the following points:
- Difference between unity and classic (no effects) when not using pcie_aspm=force --> ~600 mW (~7%)
- Difference between unity and classic (no effects) when using pcie_aspm=force --> ~100 mW (~1%)
- Lack of difference between pcie_aspm=force and regular when using classic (no effects) --> ~40 mW (~0.5%)
- Difference between 10.10 and 11.04 classic (no effects) with or without pcie_aspm=force --> ~500 mW (~7%)
Notes: 10.10 was using no effects, desktop edition ubuntu (so no compiz)
Conclusions:
- pcie_aspm=force makes a difference when using unity
- pcie_aspm=force makes no difference when not using desktop effects
- when not using desktop effects, 11.04 still takes 500 mW more than 10.10 (independent of pcie_aspm=force)
So pcie_aspm=force does not fix the entire problem and (at least in my tests) only makes a difference when unity/compiz is used. This might be related to gpu usage for desktop rendering, but I don't know enough about the differences to really comment on this. If anyone knows more tests I can do to further narrow down what might be the cause, please let me know.
Greetings,
Erwin Junge