[kajsadfksdfkl]

Does anyone know if it will do any good for the dual gfx card laptops? These new acer series laptops have two graphics cards on them. One is the intel on board and one is the nVidia G-Force. It uses a technology called nvidia optimus to select one of them according to need. But Linux seems plain confused and always uses both the cards I think. Thus on windows laptops run for 4:30hr with everything turned on and it is just under 2 hours for linux.

[fader]

Optimus requires driver support to perform the switching, which so far nVidia has refused to even think of adding for Linux. Since their drivers are closed, there's not much more that can be done. It's possible that support might eventually make it into nouveau, the open-source NV driver, but it's not there now.

(On top of that there are some bits of X that need to be rewritten to be able to fully take advantage of card switching conveniently, but last I heard people were working on it.)

If power is your concern, most BIOSes will let you disable the nVidia card and force everything through the Intel hardware. But the obvious downside to this is you never get to use your fancy graphics hardware.

[protopete]

In an nVidia Optimus configuration, there is no actual switching between the IGP and GPU. The LCD display is connected only to the IGP. The discrete GPU is connected only to the PCIe bus. Therefore to display anything from the GPU, the contents of the GPU framebuffer RAM need to be copied over the PCIe bus to the main RAM and displayed using the IGP. The Windows drivers use "Microsoft detours" in the Display Driver Interposer to seamlessly direct graphics API calls from applications to the IGP or discrete GPU.

http://www.nvidia.com/object/LO_optimus_whitepapers.html

[starwed]

This was actually enough for me to avoid buying an Optimus equipped netbook I had my eyes on... :(

[Symmetry]

By turning off Optimus in BIOS I was able to get main graphics working in my work laptop, but there seems to be absolutely no way to enable external monitors for now. If you can just get normal Intel graphics, you'll save yourself a lot of trouble.

[kajsadfksdfkl]

I never use it anyway except for rare occasions like some games in which case I have to switch to windows anyway. But I don't see the option to switch the thing off.

[blinkingled]

You need a newer kernel with gpu switching support and in some cases might need to play around with kernel command line parameters or scripts to power down the unused GPU. Google for it.

In general though I avoid running Nvidia GPU under Linux.

[m0nastic]

You can try using Bumblebee[1] or Ironhide[2], as they seem to be coming along fairly well.

[1] https://github.com/MrMEEE/bumblebee [2] http://www.martin-juhl.dk/2011/08/ironhide-reporting-for-dut...

[kajsadfksdfkl]

Bumblebee did show some improvement but even if I use bumblebee-disablecard the powertop program still reports 18.7Wh drain of battery. In windows it is about 12-13. Difference of about an hour.

Will try ironhide.