ok im not talkin bout the omaha coop mod 
im talkin about THIS 
http://www.alliedassault.com/community/guides/eascya/ 
eascya says that shood work 
but when i make a dm game and wait for my friend to join 
and then type maplist and find a sp map and switch to it everything is fine untill he joins 
it gets all CHOPPY, not latency wise but like 0.4 FPS, even tho normall i get liek 100FPS in normal games, and same for him too 
why does it do this? we even tried it on a LAN!