I used to have the same issue.
The problem here is the more records you load into the gallery, the more binding processes take place, the more memory used up, the longer to load the app.
What I did was I tried to add some filters (checkboxes, datepicker, etc.) to filter data, also, I add a button with coordinate (x,y) of the gallery so that when the user clicks the button, it will load one other set of data. This helps me to reduce loading time and memory usage.
As far as I notice, the more bindings (could be the more controllers, screens), the more memory usage.