How can I improve the texture paint performance?

[[Bm8] Naoki]

By now its kinda slow and sometimes it crashes if I set the brush size any higher than 85. I did read that you could set the multithreading somewhere, but I cant find it in the performance settings, using the latest Blender 2.8 build via Steam.

My character is 430.000 verts, 340.000 faces and 685.600 tris with hair which is haircards. The UVs is decent.

I have a pretty powerful pc so that shouldnt be the problem. My specs running Windows 10:

Intel i7 7700 @ 4.20
16GB ram
Rog Maximus IX formula
Rog GTX 1080, 8GB

[Swordgun]

That's just how Blender is for the time being. Sadly.
I personally never do big brush strokes.