Ok, so an update on that super-hot Neptune (Titans will do this too). Thing was running with PS temps at >100c, chip at 60c+ at a mere 350mhz, bottom was extremely hot to the touch (these things must be laughs on carpet).
Took unit apart, found this:
Yep. Filth and crummy hardened heat sink compound. Cleaned up the chip, the box, everything, and now:
44C
0 0.7838 34.5625 27.090 75.500
1 0.7834 35.0000 27.419 79.625
2 0.7859 35.0000 27.507 67.625
3 0.7823 34.3750 26.892 67.750
4 0.7838 35.3125 27.678 60.000
5 0.7870 35.7500 28.135 65.625
6 0.7848 34.2500 26.879 63.688
7 0.7828 35.0000 27.398 65.125
500gh, 218 watts, bottom normal temp to the touch.
Moral: If your unit is running hot, try opening it up and cleaning the thing. Replace the heat sink compound, clean the old crap off the chip (if there is hardened crud on there you will break the chip when you torque down the sink) and torque the screws down "finger snug". Likewise snug them in sequence, to even the pressure.
Never dull, on to the next unit.