Mobile PCI Express Module

Mobile PCI Express Module (MXM) is an interconnect standard for GPUs (MXM Graphics Modules) in laptops using PCI Express created by MXM-SIG. The goal was to create a non-proprietary, industry standard socket, so one could easily upgrade the graphics processor in a laptop, without having to buy a whole new system or relying on proprietary vendor upgrades.



Generations
Smaller graphics modules can be inserted into larger slots, but type I and II heatsinks will not fit type III and above or vice versa.

Dell's Alienware m5700 platform uses a heatsink that will fit Type I, II, & III cards without modification.

MXM 3.1 was released in March 2012 and added PCIe 3.0 support.

First generation modules are not compatible with second generation (MXM 3) modules and vice versa. First generation modules I to IV are fully backwards compatible.

Specification
MXM is no longer freely supplied by Nvidia but it is controlled by the MXM-SIG controlled by Nvidia. Only corporate clients are granted access to the standard. The MXM 2.1 specification is widely available.

Other uses


The Qseven computer-on-module form factor uses a MXM-II connector, while the SMARC computer-on-module form factor uses a MXM 3 connector. Both implementations are not in any way compatible with the MXM standard.