AMD Athlon X2 BE-2400 (Brisbane Core, 2.3 GHz)
AMD's Athlon X2 series is only available on the 65 nm Brisbane core (G1 or G2 stepping). Introduced as a high efficiency model, it delivers exactly the same performance as the Athlon 64 X2 running at equal clock speeds. However, its reduced core voltage (1.25 V max rather than 1.35 V max) makes sure that these processors stay within a 45 W power envelope, which is less maximum power requirement than you will find in the Intel portfolio. Of course, it's important to know that the TDP only defines what the maximum power consumption could be; it doesn't mean that the platform requires it in every case.
The fastest Athlon X2 is the BE-2400, which runs at 2.3 GHz; this model is only available based on the latest G2 Brisbane core. The G1 models BE-2350 and BE-2300 run at 2.1 GHz and 1.9 GHz, respectively.
Again, Cool'n'Quiet throttles the CPU speed to 1.0 GHz during idle time.