My friend invited me to play play (he's host) and we had no issues playing the game, i had about 60-80 fps at average.
As soon as i join gm_boreas as host (me as host) the game oly reaches 1-15 fps, 2 fps at average (even with gmod_mcore_test 1)

The only joke about this is that my friend has a low end pc and me? I? dunno... and me a high end pc.
How to fix this or what could this be?
(Sorry for bad grammar, im german)