While the performance market has been neck and neck for the past year, AMD has enjoyed a lead in the value market since the release of their Duron processor. Although the Celeron has recently gained a 100MHz front side bus, boosting performance, AMD's Duron has an equivalent 200MHz bus in addition to a 133MHz memory bus in its favor. With the release of the Duron 900MHz, we can add a 100MHz frequency advantage to that list. AMD's latest addition to the Duron family is nothing more than what we would call a "service release;" basically, the same Duron we have grown accustomed to, running 50MHz faster.

The CPU contains 25 million transistors and takes up 100mm˛ of die space. In comparison, the Thunderbird contains 37 million transistors and takes up 120mm˛ of die space. The Duron is being manufactured on a .18 micron aluminum interconnect process at AMD's Fab 25 in Austin, Texas, alongside AMD's aluminum Thunderbirds. Like the Thunderbird, the Duron uses the Socket A form factor. Socket A is less expensive than Slot A to manufacture, and also allows more flexible system designs. There will be no Slot A Duron at all so you will not be able to use a VIA KX133-based motherboard with the Duron. Socket A is comparable to Intel's Socket 370 FC-PGA connector.

The Duron has a thoroughly modern CPU core design that leverages much of the AMD Thunderbird's technology. It sports 64K of L1 data cache, 64K of L1 instruction cache, three independent integer pipelines, three address calculation pipelines, and a fully pipelined, out-of-order, three-way floating-point engine. The actual silicon layout is different for the Duron and Thunderbird, but from an end- user's perspective, the Duron and Athlon core are functionally identical.

The Celeron sports only 16K of L1 data and 16K of L1 instruction cache. Four times the L1 cache is not insignificant, and can lead to a massive performance boost. At the same time, the large amount of L1 cache may be responsible for the Duron's relatively high power usage.