Socket 423 (PGA423)

Socket 423, also called PGA423, is a Pin Grid Array (PGA) socket introduced together with Pentium 4 microprocessor family in November 2000. The socket supported only Pentium 4 CPUs with Willamette core and was replaced with socket 478 just in 9 months after its introduction.

The size of PGA423 socket is 2.1" x 2.1" (5.33 cm x 5.33 cm). The socket has 423 pin holes arranged as 39 x 39 matrix with 26 x 26 section of pins removed. No corner pins in the socket are plugged, but, because the 26 x 26 section is removed not exactly from the center of the pin grid, there is only one way to insert the CPU into the socket.

  Supported processors  

Desktop Pentium 4 Willamette (1.3 GHz - 2.0 GHz)

There are no CPUs from other manufacturers compatible with socket PGA423.

  Compatible package types  

Organic Land Grid Array package with Integrated Heat Spreader (IHS) on 423-pin interposer.

The picture on the right shows the bottom view of the 423-pin package that fits into the Socket 423.

  Upgrading socket 423 motherboards  

To determine the fastest processor for your motherboard you'll need to:

• Determine manufacturer and model of your motherboard,
• Search on manufacturer's website for the motherboard model.

It is possible to use socket 478 Pentium 4 CPUs with Northwood core in socket 423 motherboards with the help of special CPU upgrade adapters, such as Powerleap PL-P4/N or Upgradeware Technology p478. These adapters plug into socket 423 and have a socket 478 on the top. At the very least the adapters can be used to upgrade to Pentium 4 2.6 GHz or Pentium 4 2.8 GHz with 400 MHz FSB. Motherboards supporting 533 MHz FSB can be upgraded to even faster Pentium 4 processors.

  Processor Installation  

For processor installation instructions please look at your motherboard manual, or go to this page on Intel website (scroll down to "Processor Installation" section).