Hi,
I'm in a situation like yours, the game runs fine on my static computer, but it runs like crap on my laptop.
The anti aliasing option coming with the update helped a bit to get more FPS, but the main setting availabel at the moment seems to be the resolution.
By default, I'm at 1600 x 900 and downgrading it to 1280 x 720 (which is the minimum) gives me FPS but the UI looks very bad.
I think the most cpu/GPU intensive is the quality of effects and models (characters, water movements, lights ...)
I used stuff like game booster by Razer and others windows optimizing softwares, the gain isn't big but it still helps.
By default :
1600 x 900
Anti aliasing max
FPS (only in the first place of the game) : 10-20
Whent putting anti aliasing to mini :
FPS : 15 - 25
When putting in 1280 x 720 :
FPS : 20 - 27
Some would say that about 30 FPS is okay, but it's the performance when my laptop is "cold", after a few minutes, the FPS drops to 10.
I've already been searching for low end PC mods, but there is'nt yet.
The most efficient solution I found, still unplayable, is to modify the compatibility mode of the game and launch it with 640 x 480 resolution, the FPS gain is obvious but the UI doesn't work under the 1280x720 limit.
But there's a starting with this tool : http://www.nexusmods.com/pillarsofeternity/mods/27/?
The Idea would be to extract the assets to get a zero compression folder which would take more disk space but need less ressource to be used.
You can read the discussion on this mod, there are many troubles using it but maybe, with a new version, it will be possible.
Anyway, I hope a new update would come with settings about quality models and shaders.
I know it's a great game, but it's almost impossible to play it for more than 2 hours without over heating the pc.