Memory performance
These memory performance tests are a good way to start, because they'll show us whether the KT266A chipset gives our Athlon XP 1900+ test system any advantage. However, memory performance alone does not make a fast computer, so keep in mind that these scores are primarily just for show. The results are useful mainly because they help explain what comes on the following pages.

First up is the memory test from SiSoft's Sandra, which is a modified version of the Stream benchmark. Here's how things stack up:

As it has been for the past year, the Pentium 4 is fastest here. However, Athlon XP 1900+ gets a nice boost from the KT266A chipset; its FPU and integer scores jump up by a fair amount—more than one would expect with a 66MHz clock speed jump alone.

Now let's look at it another way with Linpack.

To understand what this wild-looking graph is telling us, consider the results at a couple of different places. First, compare the megaflops numbers at a matrix size of about 64K. Here, the CPUs are able to do the math entirely inside their L1 caches, and the Athlon XP is far and away the fastest.

Next, compare the numbers at about 192K, where the data to be processed fits entirely in the processors' L2 caches (with the exception of the Celeron and Duron). The Pentium 4's L2 cache is fastest here, though the Athlon XP 1900+ isn't too far behind.

Finally, compare the numbers out at 1800K, where the processors must all access main memory constantly in order to retrieve data. Here, the processors compare about like they do in the Sandra memory test; the P4 is fastest, followed by the Athlon XP/KT266A combo, then by the other DDR systems. The Pentium III and the value processors use slower, plain ol' SDRAM, so they're quite a bit slower.

Until the Athlon XP's front side bus gets faster than 266MHz, I wouldn't expect to see it challenging the Pentium 4 in raw memory bandwidth. The Pentium 4 simply excels here, and its ample memory bandwidth is a big contributor to the P4's solid gaming and multimedia performance. However, these numbers don't mean nearly as much as the scores in the performance benchmarks that follow...