If you're experiencing a very slow startup time, or very slow execution while working, then it could be related to your anti-virus software. We have seen this several times, and the solution is to simply add MEMENTO.EXE in your anti-virus software's exclusion list, or whitelist.
Another possible cause is the new Face Recognition feature, which can slow things down depending on the speed of your computer, and the size of your images. You can turn this feature off by clicking on the small "face" icon in the book view in the upper left area of the software.