Direct Media Interface

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In computing, Direct Media Interface (DMI) is Intel's proprietary link between the northbridge (or CPU) and southbridge (e.g. Platform Controller Hub family) chipset on a computer motherboard.^[1] It was first used between the 9xx chipsets and the ICH6, released in 2004.^[2]: 1 Previous Intel chipsets had used the Intel Hub Architecture to perform the same function, and server chipsets use a similar interface called Enterprise Southbridge Interface (ESI).^[3] While the "DMI" name dates back to ICH6, Intel mandates specific combinations of compatible devices, so the presence of a DMI does not guarantee by itself that a particular northbridge–southbridge combination is allowed.

DMI is essentially PCI Express, using multiple lanes and differential signaling to form a point-to-point link. Most implementations use a ×8 or ×4 link, while some mobile systems (e.g. 915GMS, 945GMS/GSE/GU and the Atom N450) use a ×2 link, halving the bandwidth. The original implementation provides 10 Gbit/s (1 GB/s) in each direction using a ×4 link. The DMI provides support for concurrent traffic and isochronous data transfer capabilities.^{[2]: 3 [4]}