Socket 478 / Socket mPGA478B
Socket 478 (mPGA478B) is a Pin Grid Array (PGA) socket for microprocessors based on Intel NetBurst architecture. This socket was introduced in August 2001 as replacement for short-lived socket 423. The socket 478 supports desktop and mobile Pentium 4 and Celeron processors from 1.4 GHz to 3.46 GHz with effective front-side bus frequencies 400 MHz - 1066 MHz (100 MHz - 266 MHz QDR). This socket was phased out in favour of socket 775 (LGA775).
One major difference between the socket 478 and older sockets is the socket size. The distance between pin holes in socket 478 is twice smaller than the distance between pin holes in the socket 370, which was used by older Celeron, Pentium and Pentium III families, and in the socket 423 used by first generation of Pentium 4 microprocessors. This results in much smaller socket size - only 1.38" x 1.38" (3.5 cm x 3.5 cm). Another difference between socket 478 and earlier sockets is the arrangement of pins. Pentium and newer CPUs, including socket 423 Pentium 4 microprocessors, had pins arranged as two grids where one grid was diagonally shifted relative to another grid by 1/2 of the distance between pins. In mPGA478B the pins are arranged as one grid, that is the same way as in Intel 80486 and older microprocessors.
The mPGA478B has grid size 26 x 26 with a 14 x 14 section removed from the center of the grid. Two pin-holes in one corner of the socket are plugged, so there is only one way to install the CPU. The total number of pins is (26 x 26) - (14 x 14) - 2 = 478.
All processors in the table below will physically fit into the socket, but not all of them are supported by all motherboards. If you're upgrading an old computer system please make sure that the CPU is compatible with your motherboard. Please see "Upgrading socket 478 motherboards" section below for information on how to determine what microprocessors can be supported by your motherboard.
Note: All processors are in 478-pin micro FC-PGA2 package, unless stated otherwise.
Mobile Pentium III-M and Pentium M microprocessors use different type of socket. There are no CPUs from other manufacturers compatible with socket 478.
Compatible package types
478-pin micro FC-PGA (does not contain integrated heatspreader)
Please note that there are three different 478-pin packages, and only one of those packages is compatible with socket 478. The picture on the right shows the package that fits into the mPGA478B socket.
Upgrading socket 478 motherboards
To determine the fastest processor for your computer you will need to know your system brand and model for branded computers like Dell, HP, Gateway, etc, or make and model of motherboard in your computer.
For upgrade information for ASUS, DFI, ECS, Gigabyte Technology, Jetway, MSI, PC Chips and a few other motherboard brands of motherboards please check CPU-Upgrade motherboard database.
For processor installation instructions please look at your motherboard manual, or download installation instructions for boxed Intel Pentium 4 microprocessors from Intel website.
Important notes about Pentium 4 CPU installation:
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