Specifications

Athlon XP features

QuantiSpeed™ architecture
266MHz front-side bus
462-pin Socket A interface
128K on-chip L1 cache
256K exclusive on-chip L2 cache
Fully pipelined superscalar floating point engine
3DNow!™ Professional technology and superscalar MMX™ technology
0.18-micron manufacturing process
1.75V core voltage
37.5 million transistors
128mm^2 die size

Athlon XP's enhancements

As you can see from the specs above, Athlon XP incorporates the Palomino enhancements present in Athlon 4 and Athlon MP, they've just been lumped under the QuantiSpeed architecture name.

If you recall, the new core brings with it hardware data prefetch logic. This essentially increases the efficiency of the L2 cache, and is one of the most significant performance enhancements added to the new core. In addition, Intel's SSE instructions are supported, we've found that this increases the performance of the processor with multimedia applications for tasks such as video encoding, Adobe's Photoshop program is another application that benefits from the SSE instructions.

In addition, the number of entries in the L1 data translation look-aside buffer (TLB) has been increased and the L2 TLB's (both instruction and data TLBs) now boast a new exclusive architecture.

Core voltage of Athlon XP remains the same as Athlon - 1.75V - although Athlon XP consumes 20% less power than its predecessor. Additionally, the die size has increased from 120mm^2 to 128mm^2 and the transistor count has gone from 37 million transistors to 37.5 million. Finally, AMD has implemented a slightly different layout of the Athlon XP core itself to reduce power consumption:

Thunderbird on the left, Palomino on right

This is a brief recap of the changes AMD has implemented with its Palomino core. If you're unfamilar with the new changes, please refer back to our Duron 1.0GHz or Palomino Performance Preview articles for more information.

Front/back of Athlon XP

Besides the hardware changes, you've obviously noticed that AMD has slightly changed the name of its flagship processors. The new Palomino processors are denoted by the new "XP" designation. Unlike previous 7th generation processors, the Athlon XP processors are branded based on their performance relative to conventional Athlon processors. So in the case of the Athlon XP 1800+ we're testing today, the chip offers similar performance as AMD's previous Athlon product at 1.8GHz even though it's only running at 1.53GHz.

If you recall our Palomino Performance Preview, our 1.2GHz Athlon MP offered similar levels of performance as a conventional Athlon at 1.4GHz, so the numbers definitely match up. And as far as AMD's marketing department is concerned, the new model numbers also help the company keep up with Pentium 4 in the eyes of the mainstream consumer.

To prevent confusion, AMD will also provide the exact clock speed of the processor on the packaging, but consumers will have to read the fine print to see it.