Is the Linux port legit?

Meaning, is it native? I could run this game no problems on Windows 7 with a GTX 670 and Physx on, yet I can’t seem to do that with a 970 on Linux. I’m on kernel 4.8 with Nvidia proprietary drivers yet I get a frame range of 35-50. Is anyone else encountering this problem? For extra information, I’m running a 3570k @ 4.4GHz, running xfce + compton with glx backend, and have the ForceFullCompositionPipeline on for my four monitors. I’ve tried combinations of them on and off and I still get issues. Even turning the settings of the game all the way doesn’t improve the framerate that much. What gives?

grabs popcorn

…been considering having a go at running this in Linux myself.