Memory performance
We start out with memory performance to keep it logically separate from the rest of the benchmarks, because the memory tests are a little more theoretical, and a little less about real application performance, than the rest of the benchmarks.

There are clearly three classes of systems here: Pentium 4s based on RDRAM offer the most memory throughput, followed by Pentium 4s with DDR memory. Athlon XPs take the bottom three slots, as we've come to expect in this test. Let's get a different kind of visual on it with Linpack:

If you're new to Linpack graphs, look carefully. The left half of the graph is about floating-point performance using the L1 and L2 caches, and the right half is about FP performance when operating on data in main memory. You can see how the Pentium 4 "Willamette" has half the L2 cache of the Pentium 4 "Northwood," and you can see how the Athlon XP's 128K L1 cache is markedly faster than its L2 cache. You can also see that the Athlon XP's total on-chip cache size is effectively 384K, because the L2 cache doesn't replicate the contents of the L1 as in the Pentium 4.

The Athlon XP 2100+ peaks out higher than anything else, but the Northwood's very fast 512K L2 cache allows it to run quite a bit faster at matrix sizes above 128K. Once we reach main memory, the DDR systems tend to bunch up, as do the RDRAM systems. The one exception is the Northwood 2.2GHz, which makes better use of DDR memory than the rest of the field.