Pentium® 4 (LGA775)

The introduction of the LGA775 socket in June 2004 brought about one of the most fundamental changes in CPU mounting since the move away from soldering the processor to the motherboard.
Instead of outfitting the processor with hundreds of easily bent pins the back became covered in contact pads while the pins were moved into the socket itself. This meant if you were to accidentally dropped your CPU you wouldn't render it useless by bending or snapping a pin. Of course you could bend the pins in the socket itself, but this is generally less likely, and the boards came with a cover that could be fitted when a processor wasn't fitted.
The clamping mechanism also meant the CPU could not be dragged from the socket if it became stuck to the thermal material on the heatsink and the heatsink was removed.

An LGA775 CPU

Prescott

The new socket was debuted with the existing Prescott core Pentium 4's, and inherited all there old problems.
The extra pins allowed for more power inputs which allowed the clock speed of the Prescott core to be ramped up however due to a more plentiful and stable power source.

The launch chips were all 800MHz FSB (4 x 200MHz) parts, running at speeds of 2.8 - 3.6GHz. Intel had also moved to a numbering system for the processors and so these chips became the 520 (2.8GHz) to 560 (3.6GHz) chips, the 5 indicating the Prescott core series, while the second number indicated the relative speed within that series of chips, the technology world all developed syncronised migraines.
Heat was quickly becoming an issue however, the 3.6GHz part already had a TDP of 115W.

There was also a series of Prescott's which were labeled 5x5 and 5x9 with a 533MHz FSB (e.g. 515 for the 2.93GHz, 533MHz FSB part, 519 for the 3.06GHz part). These followed the same convention as the 'A' derivatives on Socket 478 and had no hyper-threading.

The 'J' derivative came in October 2004 and replaced the standard versions, adding the XD bit (eXecute Disabled) as supported in Windows XP SP2 to help protect the system against executing malicious code. This replaced all previous Prescott models.

The 570J (3.8GHz) was launched in November 2004 and remains the joint highest clock speed (with the Prescott-2M version) part ever released by Intel.

Finally there was an EM64T enabled version of the Prescott core, on parts 5x1, 5x6, 511, 517, 519K, 524, and OEM parts labeled 'F'.

The erratic naming and numerous slightly different SKU's made actually getting the Prescott that you wanted somewhat difficult.

Prescott-2M

The Prescott-2M was released in February 2005, just over a year after the initial Socket 478 launch of the Prescott core, and saw a selection of tweaks and improvements to try and improve performance.
All Prescott-2M chips (known as the 6x0-series at launch, 620 for 2.8GHz up to 670 for the 3.8GHz part) featured hyper-threading, EM64T, a 800MHz (4 x 200MHz) front side bus, and XD-bit. Additionally all except the 620 featured EIST, as seen in mobile chips, which say the system reduce the multiplier to 14x while idle to save power and therefore reduce heat. The 620 did not feature this as it already used a 14x multiplier (14 x 200MHz).

On November 14th 2005 two 6x2 parts were introduced, debuting Intel's Virtualization Technology. These chips (the 662 and 672) came in 3.6 and 3.8GHz.

Overall the Prescott-2M was a definite improvement over the original Prescott, but not enough to make it competitive in its own right.

Cedar Mill

Simply a 65nm die shrink of the Prescott-2M core. No new features, no per-clock improvements, but the heat issues were reduced, TDP at 3.6GHz was 86W compared to 115W for the equivalent Prescott-2M.
The Cedar Mill core was numbered 6x1 and 6x3 (6x3 for chips with Virtualization Technology) and released at speeds of 3.0 - 3.6GHz.

Archived Pentium® 4 (LGA775)

There are presently no LGA775 Pentium 4's in the CPU archive.