So at cpu at 70% load and fan at 3600 your temp is 74C?
Mine would be:
87C, 6200 at 70% load (over time)
so yours is definitely operating much better.
If this is indeed the case then the most likely culprit would be the nasty paste glob issue.
And if it's paste, it may need a settling period. In other words,
the thermal characterisitcs may change as the the paste goes through thermal cycles.
or whatever