The game always runs under 20fps

[arXiteK]

Hello I just decided to play amnesia again after a while. However, the game always runs with terrible fps, usually around 15-17. My spec is as follow:
OS: Win 10
Processor: Intel Core i5-6300HQ
Memory: 8GB Ram
GPU: NVIDIA GeForce GTX 950M
I have already set the game to run using the high-performance graphic card in the NVidia 3d manager, and my driver is up-to-date. I also try to lower my resolution to 1366x768 but the framerate still stays at 15fps. I have also tried to disable fps limit but it didn't work either.
I included the hpl.log here in case you guys need to check it

[hmccord3333]

Try uninstalling it then reinstalling it if that doesn't work then try setting the graphics at the lowest settings.

[Mudbill]

Do you have SSAO enabled? If so you should turn it off.

[arXiteK]

Do you have SSAO enabled? If so you should turn it off.

It doesn't work, and turn the graphic to low setting doesn't work either. It seems like the game limits its fps to 17 or something, because no matter what I do, I still get ~17 fps

[Mudbill]

Has it always been this way or did it work fine at some point in the past?

[arXiteK]

Has it always been this way or did it work fine at some point in the past?

Well actually this is the first time I installed the game on this laptop, so I can't tell.
Weird though, it can run Soma pretty good, but can't run this game

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UPDATED: I tried running the game in 1600x900 windowed mode, the game ran at ~120fps at highest setting. However, when I tried 1920x1080 windowed, it went back to fullscreen and the fps dropped back to below 20fps. The issues also occurred when I tried 1600x900 full-screen mode

[Mudbill]

So it's the fullscreen that is causing it, and running it in windowed gives high FPS? That's rather odd, but not unheard of, though I can't say I know the solution by heart.