does this mean that it's a 1.8Ghz machine?

Athlon XP Desktop 1800+ Processor- Retail Boxed 1.53 GHz Socket A processor with QuantiSpeed Architecture. Requires a motherboard that is Athlon XP optimized. Processor in a box with heatsink and fan. Pin Grid Array (PGA) for mounting in a socketed infrastructure. Based on the 0.18 micron aluminum process technology. 266MHz Advanced Front Side System Bus for superior performance on data-rich applications and 3DNow! Professional Technology, which adds 52 new instructions for advanced 3D and Multimedia performance. Performance-enhancing cache memory features 128K of L1 cache and 256K of integrated, on-chip L2 cache for a total of 384K full speed, on- chip cache. QuantiSpeed architecture optimizes work per clock cycle so the Athlon XP has superior overall performance. * AMD's QuantiSpeed Architecture incorporates: - 9 issue, fully pipelined, superscalar micro-architecture. - Superscalar, fully pipelined Floating Point Unit (FPU). - Hardware data pre-fetch. - Exclusive and speculative Translation look-aside buffers (TLB).

The model numbers were meant to equate the XP cpu's relative performance when compared to an Athlon Thunderbird...

An XP 1800+ was supposed to provide performance equal or greater than a theoretical Thunderbird running at 1800mhz...even though the XP is at 1533mhz...

The new model numbers (2400 and up) are designed to equate relative performance compared to the P4...

AMD is trying to make the general public aware of the fact that a higher mhz speed alone does not mean superior performance...

The practice has confused a lot of people...