dont use power limit to reduce vrm temps. That simply makes the card struggle to stay stable even more flipping back and forth with voltages and frequencies.
Use Afterburner to reduce clocks and voltage directly.
Id say a good negative 300mhz core offset with a big chunk of voltage reduction would be better than lowering the power limit. If it was a VRM temperature issue, it will "solve" the issue right then and there.
This does not rule out a component failure though, simply a temperature issue.