Raise power limit to its highest (which also adjusts max temp. Since these cards barely overvolt, crank that too. Just make sure you are not hitting the power limit and throttling (see this in msi afterburner)
As I have already mentioned, you nee to raise the power limit all the way which will move the temperature target. Your next steps are to raise one thing at a time, core or memory. Find its limit, then back it down 25 MHz and do the same on the other. Once you find that limit, back it down 25 MHz or so, and then have both raised and see if you are stable.