well then IDK about your watercooling.
at 1.3v at 3.9ghz (on a q9450 which would probably yield 4+ on a comparably binned qx) i get absolute maxes in the low 80s on air for linpack, which, for an hour long stress test, isn't too bad imo, seeing as it barely pokes into the 50s for normal use.
I'd say with good airflow and smart voltages those procs can definitely handle this even in a skulltrail config. And i mean, this is just to declare a stable system, so high temps on this really aren't too much of an issue as long as the resid norms are consistent, at least insofar as stability.
At least give it a try.