Unlike Celeron vs. P-III which share the exact same silicon (with the Celerons then getting crippled to 66 MHz bus and half the L2 cache), the Duron die is actually different from the Athlon's. It's physically smaller, giving more chips per silicon platter, and better yields. And it's a fresh new CPU core that has been _designed_ for high speed grades to yield well, again unlike Intel who still tweak and wrestle ye olde PentiumPro core to unknown heights. Need I say 1.13GHz disaster?
Regards, Peter