As you know, the Pentium 4 Prescott is Intel's third generation Pentium 4 core. The first, code name Willamette, became popular due to its performance advantage over the last Pentium III Tualatin while consuming much more power.

The second generation, named Northwood, is based on a 130 nm process and definitely is the best Pentium 4 core available today, as it offers decent performance paired with impressing overclocking margins. We already had several Northwood processors that smoothly got along when clocked at 4 GHz, with only conventional CPU coolers.

Today, there are many P4 processors available, based on either the Northwood or the Prescott core. Clock speeds nowadays start at 2.4 GHz and end at 3.4 GHz, while there are over 20 different versions from which to choose. The following table shows the differences between the different versions:

The higher the number is up in the alphabet, the more advanced the processor is. However, a letter is only applied if there are two different models with the same core clock speed, such as the Pentium 4 at 2.4 GHz and a FSB400 or the Pentium 4B at 2.4 GHz and a FSB533. The Pentium 4 C represents the the FSB800 versions that also have HyperThreading. The only exception is the Pentium 4 3.06 GHz, with a FSB533 and which was the first CPU with HyperThreading. An E is the represents the Prescott models with a 1 MB L2 cache, while those versions with only FSB533 are flagged with an A.