Nobody'll really be able to tell you if it's stable 7 minutes in unless it has some sort of error (in which case, no). If there's no errors 2 hours in, it might be stable. 12, it probably is. 24 hours though is what you'd want to be error-free for in stability testing.
If you're just testing the waters, making sure your OC isn't going to catastrophically fail, I don't see any real harm in running prime for 30 minutes to an hour before bumping it up a little (as 4.0 is a little low compared to the 4.6 or 4.7 most people achieve on air).