Home

IBM EGA Card  -  Extra RAM


The IBM EGA card contains 8 RAM chips (pictured here) that together provide 64 KB of video RAM.

* Some programs will not display as intended when only 64 KB of video RAM is present.  More information here.
* CheckIt diagnostic software will report video RAM errors if less than 256 KB of video RAM is fitted.  More information here.


Graphics Memory Expansion Card

This is a memory card that plugs into the IBM EGA card, providing the IBM EGA card with additional video RAM.

ibm_ega_graphics_memory_expansion_card_1_s.jpg ibm_ega_graphics_memory_expansion_card_2_s.jpg Click on photo
for larger view


The memory card is IBM part number 1501201
On eBay, and elsewhere, you may find the card listed under numbers found stamped on the card: 6480099, 1501530, 6323468.
Box photo is here.

Each RAM chip provides: 16K worth of 4 bits = 8 KB.  Thus, each row of chips provides 64 KB of video RAM.

As pictured above, when IBM supplied this memory card, only the bottom row of RAM chips was populated.
Adding the memory card, as supplied (only one RAM row populated), to the IBM EGA card, adds 64 KB of video RAM to the IBM EGA card, bringing the total to 128 KB.


Graphics Memory Module Kit

To get the extra two rows of RAM chips, one ordered the 'Graphics Memory Module Kit' from IBM.
Adding those two rows of chips brought the total video RAM to 256 KB.

Box photo is here.

In one document (here), IBM has referred to the kit as the 'Graphics Memory Expansion Kit', but I suspect that is a mistake.

The kit is IBM part number 1501203


RAM chips

These are a specific type of RAM chip.

The -15 in the part number indicates a speed rating of 150 ns (chips are not to be run faster than 150 ns).
The -12 version (120 ns) of the chip can be used instead, but note that use of those versions will not make the video RAM run faster (the card circuitry controls that speed).

Chip Data Sheet    Comment
IMS2620P-15 datasheet Used by IBM on my IBM EGA card.
HM48416AP-15 datasheet Found fitted to my Graphics Memory Expansion Card.
MB81416-15 datasheet These chips have been successfully used in my Graphics Memory Expansion Card.
TMS4416-15 datasheet Seen fitted to a Graphics Memory Expansion Card.  (photo)
M5M4416-15 datasheet Page 2-9 of the document here indicates compatibility with the above chips.



Installation instructions

Some installation instructions are contained in the document at here.