Hardware Zone has posted a review of the Athlon XP 2200+, which runs at 1.8Ghz.

The new Athlon XP 2200+ processor now consumes only 62.1W of power, approximately 13.5% lower than its previous 2100+ processor which is based on the 0.18-micron manufacturing technology. Although they have managed to lower the voltage, they are still behind Intel in terms of technological supremacy as the Pentium 4 at 2.53GHz actually runs a lot cooler than the Athlon XP. This means that AMD still have lots of room for improvement.

Full review here