DonanimHaber have run an AMD FX engineering sample through a battery of tests. The engineering sample is said to be a B1 stepping chip clocked at 3.2 GHz. The Turbo Core 2.0 can up the clock speed up to 3.6 GHz with all cores active, or a whopping 4.2 GHz with only 50% (i.e. 4 cores) active. Needless to say, these are likely not the final shipping clock speeds.
Purported AMD Bulldozer Benchmarks Leaked