Is it a known bug that the game lags as fuck when playing with 7 Opponents? Or is it just me?

Its known since erm...2003?
Avoid 8 player maps

You need to understand the high variance of having 8 players.

If even 1 of you have A (Shitty computer specs) or B ( a Poor connection )
It will lag horribly

If said variables dont exist the sage engine eventually lags if you move more then 100 units at the map at once for at least 2 seconds.
(Net code)