that is not about the performance of the PC. running 8 copies of diablo 2 requires you log in 8 times. waiting for connection for all 8 players. log out all 8 players after run is complete. etc.

Most of the runs last less than 2-3 minutes. logging in 8 times is around at least 1 minute. so it is a huge waste of time.

also you need to carry 8 chars to hell difficulty for all your char. that s lame