I can get to 3.838GHz (202 × 19) stable with Prime95 using both large and small FFT sets with a Zalman CNPS-9700 tossed on and Vcore set to 1.425V. Core temperature never exceeds 44.0C with the small FFT stess test or 45.5C with the large FFT stress test.
I can get to 3.90GHz (200 × 19.5) stable with Prime95 with the small FFT sets and Vcore at 1.450V, but it tends to fall over within 10 minutes using the large FFT sets.
I can boot to my desktop fine at 4.0GHz (200 × 20.0), but Prime95 falls over within a minute or so. Nice for the big four-oh amusement value, but not much else.
FYI, my ambient office room temperature is toasty 28C. But then, it is 38C outside. I could crank the AC some more, but then the rest of the house would be an icebox.