if you have a single card, having 1 wow doing 200fps is not the same as 5 doing 40. it'd be closer to 5 doing 30ish... the difference being the extra processing required for different POV and data models.

try setting your alts to 20 and see what the fps are on your main.

of course, you are saying your main's fps is good.. it just looks choppy. if that is the case, it could be latency... and the various characters are not getting their data when they need it (i doutb this.. but its a thought)

let me know if you find out anything more