I didn't touch the clock speeds from whatever the defaults are. Given the reported thermals, I'm tempted to go the other way and underclock the system. Losing ~5% performance to get a 50% reduction in power consumption would be a great deal if I can get it.

That said, I did activate EXPO on my 6000 MHz RAM sticks - which at first caused the system to hard freeze and nothing short of a CMOS clear could bring it back. But in the end, re-seating the RAM sticks seems to have sorted that one out and its running at the full rated speed now.