The Desktop King: Athlon 64 X2 3800+
The Athlon 64 X2 3800+ is AMD's dual core entry model. Although it is specified with a design power of up to 89 W, this version usually does not utilize this full envelope due to its relatively low clock speed of 2.0 GHz.
The Athlon 64 X2 certainly is no power miser, but it is an interesting option if you need high performance and still want to maintain low energy consumption. It will be fast enough for many high performance application demands, but it will also be relatively economical thanks to Cool & Quiet, which reduces the core clock speed to 1.0 GHz when the system runs idle.