i went to an empty multiplayer server, and tried changing these cvars from 1 to 4 to see if there are any visual differences and FPS differences:
so far i found these 4 without any visible effects... any idea what do they affect?
sys_spec_particles (no visible difference from 1 to 4)
sys_spec_volumetriceffects (no visible difference from 1 to 4)
sys_spec_physics (no visible difference from 1 to 4)
sys_spec_textures (no visible difference from 1 to 4)
if they don't really add to visual gameplay, i might as well set them to 1