Running out of application memory message displays repeatedly...
My experience is that most of those advisories I've seen are referring to not enough disk storage instead of RAM. However, lately I've see reports where that was also traced to useless third-party utilities.
a big +1 on posting an EtreCheck report. It is our single best tool for effectively helping you in this limited setting where we can neither see nor touch your computer.
Some of those advisories may be adware scam pop-ups. If they refer you to a site other than Apple, loose the dogs on them!