Used the mirror display on Apple TV feature of ML with the Air today to watch Olympics. Worked nicely. I like this option better than using the ipad since I am not such a fan of the NBC Olympics Live Extra app (too difficult to find what you want and I hate trying to get the screen back to landscape mode after choosing an event to watch - why can't we just use the app in landscape mode all the time???).
I never thought about it but I guess it makes sense (that multiple users will slow a system down). I wouldn't have thought that it could slow down the machine significantly though.
I have an admin account (that I generally don't log into) and an account that I use on a daily basis for security reasons. Do you think this is significantly slowing down my machine?