The ACF7P is by today's standards an average cooler. My G0 Q6600 reached core temps of mid 60's at 3.3 GHz. With a TRUE, I reached 3.6 GHz at 1.42 volts. Loaded core temps were 61 - 65 C.
So I am guessing 3.3 - 3.4 GHz. and no higher unless you get really lucky and have a chip with a really low VID.