Handling Large Scores

I'm not sure if this is a bug or not but the latest nightly build of Musescore does not handle playing large scores. I tried playing The Return of King Grand Suite, which has about 37 pages and the program slowed way down. I know, your first thought is, why is he commenting when the score is that large. However, I tested the same score in Musescore 1.2 and it worked fine.
I am running Windows 7.