Default Google+ Auto Awesome feature very slow or crashes

Just wondering if anybody is using this feature on a N4?

A friend is trying to stich together some photos and videos into a montage similar to what Google did, and the app is taking hours to complete the montage and will often crash during or at the end of the process.

OTOH I have tried a few on my N5 and they seem to work okay. The N5 is faster but we are talking about minutes versus hours! It's not that mch faster!