RahmedHere's what mastercomfig has documented:
https://docs.comfig.app/latest/tf2/cvarlist_win/
r_3dnow: Enable/disable 3DNow code
r_3dsky: Enable the rendering of 3d sky boxes
r_mmx: N/A
r_sse2: Enable/disable SSE2 code
r_sse_s: sse ins for particle sphere create
benchmark them yourself and see what you get
yoo thx!