Socket M / Socket mPGA478MT

Socket M, also called mPGA478MT, was introduced at the beginning of 2006 as a socket for Core Duo and Core Solo microprocessors. A few months later, in April 2006, Intel released Celeron M 400 series family that was compatible with the Socket M. The next family that used the socket was Core 2 Duo mobile - it was introduced in August 2006. Eventually the socket was also used by Pentium Dual-core processors and by Celeron M 500 series CPUs. The socket supports single and dual-core processors with frequencies up to 2.33 GHz and Front-Side Bus frequencies up to 667 MHz. Socket M was superceded by socket P.

Socket M - top viewSocket M - view with CPUSocket M - side view

The socket has 478 pin holes arranged as 26 x 26 grid with 14 x 14 section removed from the center of the grid. The socket has 2 pin holes at one corner plugged. Socket dimensions are 3.6 cm x 4.4 cm or 1.42" x 1.73". Similar to socket 479, the Socket M doesn't have a lever that locks the CPU in the socket, or releases it. Instead, the socket has a special actuator that needs to be turned by about half-turn to lock or release the processor.

While the socket has 478-pin holes - the same number of pin-holes as in the socket P and the socket 478, it is not compatible with them due to different positioning of one pin-hole. Mobile Pentium III-M processors can physically fit into the socket M, but they are not electrically compatible and won't work in the socket.

Supported processors

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 M motherboards" section below for information on how to determine what microprocessors can be supported by your motherboard.

There are no AMD or VIA processors compatible with this socket.

Compatible sockets

Socket 479 / mPGA478M (for motherboards supporting Core Solo, Core Duo, Celeron M 400 and 500 series, Pentium Dual-Core Mobile and Core 2 Duo Mobile)

Compatible package types

478-pin micro FC-PGA

Upgrading socket M motherboards

To determine which processors are supported by your system you'll need to determine computer model (for brand-name notebooks, like Dell or HP), or a manufacturer and a model of your motherboard, and then search on manufacturer's website for that computer or motherboard model. Most manufacturers don't post CPU upgrade information for notebooks, but sometimes you may find upgrade recommendations in manufacturer's product support forums. Also try to send an e-mail to manufacturer's custom support, or post in other computer-related forums, but don't expect many responses.

Upgrade recommendations

Your upgrade choices are:

  • The fastest socket M processors are Core 2 Duo Mobile T7600 and core 2 Duo Mobile T7600G. The T7600G has unlocked clock multiplier and can be overclocked, but it's very expensive and very difficult to find.
  • If the T7600 / T7600G is too expensive for you then consider upgrading to slower Core 2 Duo Mobile processors.
  • If your motherboard doesn't support Core 2 Duo Mobile CPUs then your best upgrade option is a Core Duo T2700.

Socket M Pin Modifications

2009-12-13 02:36:48
Posted by: Benjamin Vander Jagt

Socket M (and P) motherboards with non-Intel chipsets can often be pin-modded to overvolt/undervolt and overclock. Intel-based motherboards usually have locked Trusted Mode Enabled, but that can also be circumvented at the hardware level with some very careful modification. Celeron M 530's upwards of 2.6 GHz with very simple pin-mods have been reported, which indicates that even the fringe Core 2 based chips have very high potential with minimal work. Please read threads 390696 and 393027 from

Acer 5570Z CPU

2011-07-17 00:10:24
Posted by: rich


Acer 5570Z CPU

Celeron 500 series

2011-08-08 16:03:54
Posted by: Paco

There are faster celeron processors 500 series

560 2,13 GHz
570 2,26 "

Response: Those are socket P processors

Heatsink/cooler for T2400 on socket M

2012-01-30 16:45:21
Posted by: Snevac

Is it possible to fit a socket P cooler on a socket M CPU? I have a motherboard (from a laptop) with a T2400 CPU and I want to make a desktop of it with upgraded cooling.

Response: Notebook manufacturers tend to use proprietary heatsinks, therefore it will be difficult to find matching heatsink, produced by someone else.


2012-02-07 18:51:56
Posted by: Snevac

I am going to mill one myself out of solid aluminum with a surface area 5 times larger than the original cooler with a 60mm silent fan

Last modified: 10 Mar 2014
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