What worked for me when I ran into this “Out of Memory” problem was clearing the cache. (“File -> Invalidate Caches / Restart…”) It’s been a couple days and no further problems. Before, it was happening five or ten minutes after starting PyCharm, even with me not doing anything on PyCharm other than look at it.
I’m running PyCharm Community Edition 2016.1.4 on Windows 7 Enterprise.