Yes, ultrapeer mode is pretty heavy on the memory. I find that leaving the
Connect checkbox off and Accept on overnight or whenever I'm not there almost
completely eliminates the RAM drain and makes it easier to shift to full power as
needed. Left in that mode it tends to have half the usual number of connections
and there's no trying to open a lot of connections at once, which is probably what
was bogging down your connection too. Those controls are at the bottom of the
Hosts view.