We couldn’t miss the opportunity of benchmarking our processors in the extreme operational mode. So we compared CPUs on Northwood, Prescott and Gallatin cores at two frequencies, 3200MHz and 4200MHz.
For the test at the increased frequency, we set the CPU multiplier to x14: all tested processors were engineering samples with an unlocked multiplier. The system memory was working in the 5:4 mode (240MHz) with 2-5-2-2 timings and Vmem = 3.35V.
One of the reasons why we tested the processors at the extremely high frequencies is our intention to check out the potential of the Prescott core at the frequencies it is going to reach in the future. In fact, this processor only starts living a full life at 4GHz and higher. At such clock rates, the negative influence of the very long pipeline diminishes and the performance per megahertz starts to grow.
By the way, our comparative test is not quite correct with respect to the new core: neither Northwood nor Gallatin will ever reach 4.2GHz by any means save for extreme cooling, while we will surely see a Prescott-based Pentium 4 4.2GHz with a simple air cooler in the near future.
There is also not much sense in presenting the benchmark results for the Pentium 4 3.4C as it is always slightly faster than the 3.2C in the regular mode due to the higher clock rate, while at 4200MHz both Northwood-based processors show exactly the same performance, like might have been expected.
The results of processor tests at their rated frequencies brought no surprises: Pentium 4 Extreme Edition is always ahead, while the 3.2C model and the Prescott swap positions in different tests.