Terrible framerate issues

[Xerenos]

Hey,
I've been really excited to play SOMA for a while now and purchased the game through steam yesterday. First of all I'd like to point out that the game seems amazing so far and I'm really eager to progress through it, but as I have mentioned in the subject of the thread I am having issues with my framerate :/ Sometimes my FPS with be a smooth 60 (This rarely happens) but most of the time my FPS sits around 10-20 which is honestly unplayable. I've tried everything I can think of so far, I've changed all of the graphics settings to minimum which gave me around 5 more FPS, I've verified the game cache through steam, changed my resolution, played around with the refresh rate setting and also switched vSync on/off. None of these things I've tried have helped to better my framerate. My system is capable of running other (similar graphically looking) games at over 60FPS at reasonable graphics settings. My system specs are --> i5 4690k @3.9GHz, 8GB 1600MHz ram, XFX Radeon HD 6850 1GB.
I would really appreciate some help with this as I am super excited to play this game but I don't want to trash my first experience by playing with this framerate. Thanks in advance for any replies!!