Just to give an idea of what I mean by 'slow' - the whole system boots completely in under 2 mins (1 min 50 secs to be exact) - Britannica takes between 3&4 mins to get going depending on what I select.
Most other programs I use (Office/Photoshop/Quicken and the like) start up in under 10 secs. I know that Britannica is probably more complex with data/searches etc. but it does seem a bit excessive.
Doing various searches there do seem to be complaints about Britannica, so unless someone has experience of speeding it up I may just have to live with it.