How to make use of Power Management features
General Information about Power Management features
APM vs. ACPI
All ThinkPads support APM and a lot support ACPI as well, but at different qualities of implementation. Both technologies cannot be used simultaneously. So you'll have to make a choice which would depend very much on the model as well as on the state of ACPI support in the kernel.
On older models you are surely better off with APM, if they feature ACPI at all.
It seems that at least in recent models from the A, G, R, T and X series ACPI generally works fine and is a lot more flexible than APM, but with a lot of them also a Problem with high power drain in ACPI sleep has been experienced.
Please check our APM vs. ACPI success table to find out about APM and ACPI support in specific models.
On the other hand simply switching from APM to ACPI extended my X31 battery runtime from about 3.5h to 4h. This had nothing to do with Dynamic Frequency Scaling which was active in both configurations.
>(TODO: more precise and extended info should be provided here)<
How to enable certain features
The following links will take you to separate pages dealing with the various topics.
- How to make APM work (Screen Blanking, Suspend to RAM, Suspend to Disk)
- How to make ACPI work (Screen Blanking, Suspend to RAM, Suspend to Disk)
- How to make use of Dynamic Frequency Scaling (Speedstep, Throttling, etc.)
- How to make use of Harddisk Power Management features (Laptop-mode, Spindown, etc.)
- How to make use of Graphics Chips Power Management features (save even more battery power)