There are a few problems with benchmarks of this kind, though.
Benchmark results reflect the entire system configuration, including changes in bus and clock speed.
As trivial as this may sound, it does pose some serious limitations regarding the availability of possible bus speed settings if the clock speed is to remain constant. As result, going beyond 133 MHz external CPU frequency will also increase the PCI and AGP bus frequencies which, by itself, may cause a slight increase in system performance. Therefore, odd frequencies as, e.g. 143 MHz, often perform even worse than one might expect. I haven t found any commercially available modules yet that would work reliably at 154 MHz. The important finding is that running at CAS-2 and 150 MHz or above, still causes a substantial increase in performance.