If we look at Intel’s Pentium 4 which, with the introduction of the Northwood core, also saw a doubling of it’s L2 cache to 512KB, we can see an overall performance increase of about 15 to 20% in comparison to the previous, Willamette, core. Thus the addition of extra L2 cache memory will certainly help to up a processor’s performance without requiring rework of the actual processor’ executing engine or other components in the core. That AMD is expecting nothing less than a significant increase in performance from the extra cache memory becomes obvious if you take the clockspeed of the Athlon XP 3000+ in consideration, 2166MHz, which is similar to that of the Athlon XP 2700+.



Fig 2. The Asus A7N8X motherboard sporting the Nforce2 platform used in evaluating the Athlon XP 3000+.
That might sound like AMD is being overly optimistic about the performance boost they’ll get from the 256KB of extra memory, but there’s other improvements made to the Barton core that allow the Athlon XP 3000+ to do more work per clockcycle than the Thoroughbred core as found in the 2700+. Or as AMD has been pitching it ever since they came up with the performance rating; it is not the MHz that matters but the amount of instructions processed per clockcycle. But with the 3000+ performance rating they’re cutting it close as the performance gap between the 2700+ and the 3000+ isn’t as big, as the benchmarks will clearly show.