iPhoto keeps freezing on OS 10.10.2
When I try to edit using iPhoto editor the App freezes quite often. The problem is frequent, but not one which occurs on every attempt to edit. I have tried the iPhoto repair Cmd, Alt click iPhoto and tried all 5 options. This does not resolve the problem. It should not be a memory issue as I have 12gb of memory and over 200gb of free space on my Hard Disc.
This problem did not occur in Mavericks.
HELP
iMac, OS X Mountain Lion (10.8.4)