AGP Inline Memory Module

AIMM Bus Description

AGP Inline Memory Module [AIMM] defines a memory card that plugs into the AGP slot, on a PC mother board with an integrated graphics core [that don't require a Video card]. The AIMM card is use as a local memory subsystem for a graphics core integrated in a core-logic chipset. AIMM boards augment the display memory on motherboards that already have AGP circuits built in. An additional 4MB [SDRAM] of dedicated video memory is possible using an AIMM card, arranged as 1Mx32 bits. AIMM boards function in either a 3.3V AGP slot or universal AGP card slot. AIMM modules are now referred to as Graphics Performance Accelerator [GPA] cards.

The GPA [AIMM] memory boards only showed up on a few motherboard types. Mother boards using Intel's 815E chip-set and integrated graphics allowed for the GPA memory modules. Normally the GPA boards were required to improve video performance. The on-board video chip-sets provided very little video memory, an AIMM board increased that by 4MB. For optimum performance an AGP card should be used in the video slot instead of an AIMM board. I'm unsure if the AIMM memory interface ever showed up on any AMD based mother board.

The specification defines the electrical and mechanical characteristics of a GPA [AIMM] board. The board size and layout is provided. Slot and module pinout is provided, as well as design notes and layout recommendations. The recommended board is a 4 layer 60 ohm controlled impedance, with one of the layers power, one ground and two signal layers. The nominal board thickness is 62 mils

Because this interface is out-dated it should not be used for new designs.
With the introduction of the PCI Express interface this expansion bus is almost obsolete as more and more motherboards ship with PCIe expansion expansion slots instead of an AGP slot.

AIMM Board Pinout Table

The pinout for the AIMM memory module is TBD, however the pin out relates to AGP 3.3 volt and Universal connectors for pin names, but the pin out is different.
The pinout for the AGP card is listed on the main AGP Bus page.

AIMM Device Vendors

Card manufacturers are listed below, but there will be fewer and fewer vendors as time goes on.

As of 11/17/10 the page listing AGP Card manufacturers only showed development cards.
Which was kind of pointless, as there are no manufacturers developing AGP boards any longer.
So the listing OEM AGP Board Manufacturers or COTS AGP Cards has been removed.

The AGP interface is out dated and has replaced by the PCIe bus.
The interface listed on this page will be found in less and less mother boards as the PCI Express interface ships with all new computers.
However AGP slots will still be found on legacy computers, or fielded systems.
AGP style video cards are no longer being manufactured, so an AGP slot will not be found on a currently produced motherboard.
Expansion buses are listed on this site regardless of being in current production.
Of course the expansion site was originally listed because it was in production, and remains to capture the meaning and characteristics.

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Modified 7/18/2015
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