AMD's new Trinity APU, specifically the A10-5800K, has been successfully overclocked to a whopping 7.3 GHz on liquid nitrogen cooling, with the team at PC Games Hardware also achieving a 5.1 GHz overclock on air cooling. The final CPU-Z readout for the overclocked A10-5800K shows it reached 7317.74 MHz, although this is with two cores in the APU disabled, and a voltage of 1.956 V was required.
The standard AMD Trinity A10-5800K has four cores running between 3.8 GHz and 4.2 GHz, changing the clock speed as the system demands it. Naturally a liquid nitrogen cooling rig is not going to be possible on the average person's machine, but the 5.1 GHz stable air overclock on 1.616 V could be something to aim for if you purchase the mid-range processor.
For those unaware, Trinity is AMD's second-generation Fusion APU utilizing their new Piledriver architecture; Trinity combines up to four processing cores in the one unit, plus a graphics unit based on their HD 6000 GPU range. The idea is that this combination will be used in more mid-range scenarios where discrete graphics cards are unnecessary, with their FX desktop-only processor line being more suited for higher-performing machines.