Latency bad on 2out of 4 clones?

Just wondering if anyone had this problem. Start up wow np have 120-160 latency on all. start doing stuff 1-2 instances of wow go to 1000+ latency while others stay perfect. relog the bad instances they go back to 160. then run around and 1-2 get disconnected log back on those and they are 1000+. I just dont get it. i ran good all week now 1-2 windows are constantly 1000+ and im constantly relogging chars that randomly get disconnected for what seems to be no reason. Any ideas?