Both Intel and AMD have been waging a core speed war for quite a while now, with Intel really pulling out the big guns with their multi-GHz processors. Relative performance levels are still quite close, due to the differing architectures of the Pentium 4 and Athlon, which basically allow AMD to stay competitive at a lower clock speed, while Intel can seemingly raise the GHz bar anytime the company chooses. So it's really no shock that Intel has released a 3.06 GHz Pentium 4, but the new technology the processor contains is quite surprising.
Along with a high-end clock speed, the new Pentium 4-3.06 GHz also features Hyper-Threading Technology, which basically allows a single processor to appear as two logical processors to the operating system and applications. We'll get into a bit more detailed look at the technology later on, but the main emphasis of HT is in making the processor itself more efficient and utilizing clock cycles to their utmost. This is a direct departure from jacking CPU clock speeds higher and higher as the primary means of processor design, and takes a more refined approach.
This combination of 3 GHz+ speeds and a new and innovative Hyper-Threading Technology makes the Pentium 4-3.06 GHz one of the more interesting CPU releases in a long time. Not only does it have the highest clock speed you can buy on a desktop computer, but the addition of Hyper-Threading gives it that added marketing muscle of a truly significant release.
With all this talk of Hyper-Threading (HT) Technology, it's important to note that the Pentium 4-3.06 GHz hasn't really changed that much from a standard Pentium 4 Northwood. Sure, it has moved above the 3 GHz level, but adding HT to the mix doesn't mean that Intel has miraculously melded two processors into one core. Instead HT allows the processor to have its existing resources partitioned and shared, with only minor hardware changes.
This really highlights the differences between a system with multiple processors and one with multiple logical processors supporting Hyper-Threading Technology. In the first example, the actual resources are doubled, while in the second, the HT design itself allows a single physical processor to be recognized as two logical processors. This enabled the multithreaded nature of the Pentium 4-3.06 GHz processor, but it also means that each logical processor shares the same resources, such as data caches, branch predictors and execution units.
Granted, there have been hardware enhancements (such as instruction and trace cache buffers, predictors and tables) to facilitate faster Hyper-Threading performance, but this has added less than 5% to the overall core size. As in any processor design, there is a finite level of resources, and HT is all about using these in the smartest and most efficient manner.