Ok. I've done a lot of testing and fiddling. I had the same problem and this solved it for me.
I have Msi gtx 1080, ryzen 1700, 64gb ram. Was getting around 50fps with 50% gpu usage & 30% cpu. Now I'm getting around 70-110fps with around 80% GPU usage.
Very generic one, but make sure you have the latest drivers for your GPU.
Go to your EFT folder, > right click> properties > compatibility > check these : disable fullscreen optimization, Run this program as administrator, High dpi scaling override (in "change high dpi settings" )
Open Nvidia control panel > Manage 3d settings> choose EFT.
power management mode: Prefer maximum performance
texture filtering -Anisotropic sample optimization: off
texture filtering-Negative LOD bias: Allow
texture filtering-Quality:High quality
texture filtering-Trilinear optimization: On
In EFT settings > game> Set process affinity to logical cores OFF (helped me, might be different for you)
This one was the most effective for me. (especially, if you have Ryzen CPU)
Make sure you have the latest BIOS drivers. I have Asus prime x370-prime, and they had multiple updates.
If you have RAM that runs at for an example 3200mHZ, make sure it's set at 3200mHZ in BIOS. (stock bios speed is 2133mHZ). If you don't know how to get into bios, download CPU-Z . Go to Memory tab > DRAM frequency: whatever it has multiple it by 2. For example 1066 so *2 = 2132mHz, if you have 2132mHz I really would suggest you do this.
I know not everyone knows how to overclock, so if you are not sure don't do it or check some youtube videos before doing.
I overclocked my RAM from 3000mHz to 3200mHZ, and CPU from 3.0 to 3.8gHz. This part is very specific for your own RAM and CPU, and you should check yourself if you can overclock. But the RAM part is imo the most important for Ryzen. Here is video so you get Idea how to overclock RAM https://www.youtube.com/watch?v=XvmYj7b0aZ8 .
For Intel CPUs you can also overclock RAM, but you don't get as big difference as Ryzen CPUs. Overclocking CPU would benefit more.