What exactly is TLP doing that default system config wouldn't?
the difference of TLP's default config compared to a vanilla Ubuntu installation is quite simple:
- SATA ALPM is set to min_power on battery instead of max_performance
- USB autosuspend is enabled for all devices (except input and wwan devs) instead of bluetooth only
The situation is different with other distros.
For even more aggressive settings you may use RUNTIME_PM_ALL=1 to enable runtime pm for all devices.
Additional gains are:
- Easy config/enable/disable for all features compared to pm-utils' undocumented scripts
- Easy and automatic enabling/disabling of radio devices
- ThinkPad battery features
TLP's documentation contains only the facts about the settings, there is no advertising.
Taken from the ArchWiki, TLP provides optimized power saving by default (without altering its configuration files).
What it does by default (or you can make it do, I do not use it):
- control the CPU frequency scaling governor
- save more battery by disabling Turbo Boost, but at the cost of some performance
- spin down disks to save battery. However it may reduces performance or even 'brick' the HDD.
- restore the radio device state for bluetooth, wifi and wwan from the previous shutdown at boot
You can find the full list of its configuration options here, where it specifically says what it takes care of.