Just a guideline, with your cooler, that chip is safe upto 1.5v for everyday use as long as temps don't get madly high above 70c under stress testing.
1.4v will not even slightly damage the chip, at all, would jsut add a little more heat, so if you want to push it more, you can.
Oh as to the arctic silver, takes about 200-300hrs to fully bed in i believe, though do give it time to cool down and set between heavy sessions, not days on constantly at a time.