The Direct Media Interface (DMI) is the link between an Intel northbridge

Northbridge (computing)

The northbridge has historically been one of the two chips in the core logic chipset on a PC motherboard, the other being the southbridge. Increasingly these functions have migrated to the CPU chip itself, beginning with memory and graphics controllers. For Intel Sandy Bridge and AMD Fusion...

 and an Intel southbridge

Southbridge (computing)

The southbridge is one of the two chips in the core logic chipset on a personal computer motherboard, the other being the northbridge. The southbridge typically implements the slower capabilities of the motherboard in a northbridge/southbridge chipset computer architecture. In Intel chipset...

 on a computer motherboard

Motherboard

In personal computers, a motherboard is the central printed circuit board in many modern computers and holds many of the crucial components of the system, providing connectors for other peripherals. The motherboard is sometimes alternatively known as the mainboard, system board, or, on Apple...

. It was first used between the 9xx chipsets and the ICH6

I/O Controller Hub

I/O Controller Hub , also known as Intel 82801, is an Intel southbridge on motherboards with Intel chipsets . As with any other southbridge, the ICH is used to connect and control peripheral devices.- ICH :...

, released in 2004. Previous chipsets had used the Hub Interface to perform the same function. Server chipsets use a similar interface called Enterprise Southbridge Interface (ESI). Some CPUs integrate the northbridge into the CPU and use a DMI interface to the southbridge.

DMI shares many characteristics with PCI-E

PCI Express

PCI Express , officially abbreviated as PCIe, is a computer expansion card standard designed to replace the older PCI, PCI-X, and AGP bus standards...

, using multiple lanes and differential signalling to form a point-to-point link. Most implementations use a x4 link, while some mobile systems (e.g. 915GMS, 945GMS/GSE/GU and the Atom

Intel Atom

Intel Atom is the brand name for a line of ultra-low-voltage x86 and x86-64 CPUs from Intel, designed in 45 nm CMOS and used mainly in netbooks, nettops, embedded application ranging from health care to advanced robotics and Mobile Internet devices...

 N450) use a x2 link, halving the bandwidth. The original implementation provides 10Gb/s each direction (using a x4 link). DMI 2.0 (introduced in 2011) doubles the transfer rate to 20Gb/s with a x4 link.

While the interface has been called DMI since the ICH6, Intel specifies the specific combinations of devices that interwork, so the presence of a DMI interface does not itself guarantee that a particular northbridge is compatible with a particular southbridge.

Protocol

If an unrecoverable error occurs on an I/O bus, a System Error message (SERR DMI msg) will be sent via the DMI.

Implementations

The following "northbridge" devices support a "northbridge" DMI:

• Intel 915-series
• Intel 925-series
• Intel 945-series
• Intel 955-series
• Intel 965-series
• Intel 975-series
• Intel P35
  Intel P35
  The P35 Express is a mainstream desktop computer chipset from Intel released in June 2007, although motherboards featuring the chipset were available a month earlier. The P35 Express chipset supports Intel's LGA 775 socket and Core 2 Duo and Quad processors, and is also known to support...
  
  
• Intel X38
• Intel X48
• Intel P45
  Intel P45
  The P45 Express is a mainstream desktop computer chipset from Intel released in Q2 2008. The first mainboards featuring the P45 chipset were shown at CeBIT 2008....
  
  
• Intel X58
  Intel X58
  The Intel X58 is an Intel chip designed to connect Intel processors with Intel QuickPath Interconnect interface to peripheral devices. Supported processors implement the Nehalem microarchitecture and therefore have an integrated memory controller , so the X58 does not have a memory interface...
  
  

The following processors support a "northbridge" DMI and therefore do not use a separate northbridge:

• Intel Atom
  Intel Atom
  Intel Atom is the brand name for a line of ultra-low-voltage x86 and x86-64 CPUs from Intel, designed in 45 nm CMOS and used mainly in netbooks, nettops, embedded application ranging from health care to advanced robotics and Mobile Internet devices...
  
  
• Intel Core i3
• Intel Core i5
• Intel Core i7 8xx , 7xx and 6xx, but not 9xx

The following processors support a "northbridge" DMI 2.0 and therefore do not use a separate northbridge:

• Intel Core i3 2000 series
• Intel Core i5 2000 series
• Intel Core i7 2000 series

The following "southbridge" devices support a "southbridge" DMI:

• ICH6
• ICH7
• ICH8
• ICH9
• ICH10
• NM10
• Intel P55
  Intel P55
  The Intel P55 is the first desktop chipset from Intel based on the PCH chipset design. The P55 Express chipset uses the LGA 1156 socket. Compatible CPUs include the Core i3, i5, and i7 processor line along with a Pentium Processor G6950...
  
  
• Intel H55
• Intel H57
• Intel Q57
• Intel PM55
• Intel HM55
• Intel HM57
• Intel QM57
• Intel QS57

The following "southbridge" devices support a "southbridge" DMI 2.0:

• Intel P67
• Intel H67
• Intel H61
• Intel Q67
• Intel Q65
• Intel B65
• Intel HM65
• Intel HM67
• Intel QM67
• Intel QS67
• Intel X79
  Intel X79
  The Intel X79 is an Intel Platform Controller Hub It is designed to connect an Intel processor through a DMI 2.0 interface to peripheral devices...