Increase FPS without Steam

Just curious, is it possible to increase the FPS without Steam?

I know of three ways
one: buy a better system. I went from a quad core 4 thread system to an 8 core 16 thread system more than double FPS increase.
two: use one of the settings mods.
three: tinker with the game files like a couple listed here in a couple of threads.
edit: typos fix

Well this is sad. I bought a new computer with an Intel Core i7-7700 CPU, 4 core and 8 thread in it, thought it would be enough for this game without lagging. After changing the graphic details I had less lagging (16 FPS the lowest), but in recent time I have curiously less than 8 FPS. Thanks for the answer, though.

the game uses streaming build so puts a heavy load on the CPU and its threads output.
Was originally designed for future systems; not current mid ranges ones. so a quad core can be ( and for me) a big bottleneck in the data stream.