So just out of curiosity has anyone ever tried larger drams in the Intel Above Board AT the specs say that memory map settings indicate 256 x 1 drams for a total of 2mb without daughter board... I was wondering is there any reason one couldn't pop in some 1m x 1 drams of compatible timing? Even if it only uses 256 Kbit of each 1 Mbit chip in theory they should still work right? Also does anyone have the daughter card that they could manage to get some close up HIRes pictures of all the trace routings and components for me? It is absurd that so many of these cards are in circulation and no one has cloned the daughterboard for all those who do not have one... There are cloned parts for the imsai and kim1 surely this isn't too much too ask... 🤣

Predator99 wrote on 2018-10-06, 10:00:

In the mean time I had some time and decoded the DIPs for the "FIF48G PE505-16M" - inserted above. […]
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In the mean time I had some time and decoded the DIPs for the "FIF48G PE505-16M" - inserted above.

In this pile
Bought these (retro) hardware today

I got another card.

IMG_9749r.jpg
IMG_9754r.jpg

Its totally no-name ("CE 49107"?) and has 1 bank of 4164 chips on it (=64 kb). 6 banks in total, are 3MB if filled with 256k chips.
1 DIP block with 6 switches (JP1), another one with 8 switches (JP2).

Replaced the 64k with 256k chips and...:

JP1 has no impact on XMS. (Set to 12345x)

JP2:
1234x6xx 9,5
x234x6xx 9,5
12345xxx 9,0
1234xxxx 8,5
xxx456x8 6,0
x2x4567x 4,0
x2x4x67x 3,5
x2x456xx 2,0
xxx456xx 2,0
xxx45xxx 1,0
x2x45xxx 1,0
12x45xxx 1,0
12x4x6xx 1,5
123xxxxx 512
x2x4x678 above 6mb
xx345xxx above 6mb

--> working 😎 😎 😎

____
EDIT:
SW 1,2: seem to have no impact? Set to OFF.
SW 4: set to ON ...otherwise counting at POST stops below 1024k
SW 35678: see below

Still need to figure out how to set steps at 128/256/384 kb. Should be related to SW 1,2,4,5.

0M 512K --- SW35678
1M 0K --- x5xxx verified
1M 512K --- xx6xx verified
2M 0K --- x56xx verified
2M 512K --- xxx7x
3M 0K --- x5x7x
3M 512K --- xx67x verified
4M 0K --- x567x verified
4M 512K --- xxxx8
5M 0K --- x5xx8
5M 512K --- xx6x8
6M 0K --- x56x8 verified
6M 512K --- xxx78
7M 0K --- x5x78
7M 512K --- xx678
8M 0K --- x5678
8M 512K --- 3xxxx verified
9M 0K --- 35xxx verified
9M 512K --- 3x6xx verified
10M 0K --- 356xx
10M 512K --- 3xx7x
11M 0K --- 35x7x
11M 512K --- 3x67x
12M 0K --- 3567x
12M 512K --- 3xxx8
13M 0K --- 35xx8
13M 512K --- 3x6x8
14M 0K --- 356x8
14M 512K --- 3xx78
15M 0K --- 35x78

So is this a card that you have been waiting a long time for, or just something you happened upon whilst traveling the intersurf? I am asking because I would love to pursuade you to sell it, I have been looking for a single 16mb memory expansion card for an IBM AT forever I currently have 10mb between an impractical 2 card multi i/o solution, but I would love to have all the memory one a single card with the entirety of the slot dedicated to just the memory no multi i/o... I had been looking for a card that took simms, but if it is 16 meg I am happy with drams. Win 95 is slow enough on any AT class machine, but with under 16mb it is Ben Steindows.

These cards are mainly for 286s...its new to me Win95 runs on such a CPU?
The card you are asking for will take up to 2.5 MB but not 16 MB...

I have referred to this post many times, has this information/ thread been stickied and added to a wiki?

I hadn't realised that I didn't post in this thread, but here is another Everex card, the EV-178:

It supports up to 8MB (of exclusively EMS, I believe), and is enabled by the attached driver.

There is a 4 way dip switch block, which is explained by the interactive setup tool:

Driver and setup utility are here below. Note that the setup utility must be run in order to configure the card hardware for the current installed amount of memory - it doesn't appear to be possible to configure via physical jumpers.

In addition, there are two jumpers on the board which I do not currently have any documentation for. Otherwise the driver works perfectly and adds 8MB EMS to be 286 systems.

TTI 8644
Cards does not look like that...but it works. I have 2 of them and both behave the same. With the configuration shown on the photo it adds 512 kb to an IBM AT with 512 kb on board resulting in 1 MB in total.
I tried around 10 settings and didnt manage it to set a starting adress above 1MB. So this card seems to be like the "G-9 SIX PAK PLUS" which fills the memory below 1MB:
https://stason.org/TULARC/pc/memory-cards/AST … X-PAK-PLUS.html
Maybe I investigate this in the future but at the moment I do not see a reason to use such card...

Populating hardware UMB on a device that otherwise lacks them (or performing surgery to add a banking latch and mapper chip, to turn it into a hardware EMS card) are both valid, IMO.

286 (which cant exit flat mode once entered (cleanly!)) With DOS 6.22, and cdrom/nic drivers, for instance.

Purposefully NOT POPULATING certain chip slots (driven by option roms in other cards) to avoid bus being driven, with other areas left populated, and the use of hiram to turn it on for UMB use, for instance.

Another 'bastard' use might be putting PROM chips of appropriate density in certain areas, and using it to store a custom option rom (xtide, pxe, etc)

Next card. Manufacturer is "CEI", see also here
Unkown ISA-Cards
Quite surprising I didnt find anything about it:

EDIT: I think its the "Computer Elektronik Infosys of America Inc" "RAMFlex"
https://archive.org/details/PC-Mag-1989-12-12 … e/2up?q=infosys
https://books.google.de/books?id=JzoEAAAAMBAJ … ownload&f=false

It can hold 8 MB and has 3 DIP blocks, A(6)-B(8)-C(8) from left to right.

Already found out block C is for setting the starting adress. Blocks A+B should be set as shown in above picture:
12345678 DIP Mem Start
00000111 1
00001000 1,128
00001001 1,256
00001111 2
00010001 2,256
00011000 3,128
00011101 3,768
00011111 4
00100000 4,128
00100001 4,256
01000001 8,256
10011101 3,768
00011101 3,768

It seems DIP 1 doesnt matter.
DIP 2 add 8192k
DIP 3 adds 4096k
DIP 4 adds 2048k
DIP 5 adds 1024k
DIP 6 adds 512k
DIP 7 adds 256k
DIP 8 adds 128k
The calculation doesnt fit 100%. Maybe its related to fact that the board I am testing with has only 512kb onboard. With the setting "00000111" the additional RAM is detected by the BIOS.

Some work remaining here. There will also be a setting for the RAM size. And also for EMS with I/O port and page frame.

Found..would be really nice to get the drivers....

Another CEI...not tested yet

CEI 218621
M079110
66707.00.5.12 REV.A

Predator99 wrote on 2025-02-13, 20:00:

Another CEI...not tested yet […]
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Another CEI...not tested yet

CEI 218621
M079110
66707.00.5.12 REV.A

As expected, configuration of this CEI card seems to be the same as for the card above. Setting on the photo adds 4 MB of RAM to an IBM AT with 512kb onboard.

Would be really nice to get the full documentation and/or EMS driver for this. But I cannot find anything.

It might be possible to figure it out by seeing which pins on the card edge are actually connected to stuff. The most sensible way to trigger the ems window move is a write to an IO port. Seeing what is actually connected to the right pins for that can help figure that out.

A BASIC program can do the IO write, and do PEEKs to see if a window swap happened.

In fact, one COULD just exhaustively test the whole adapter region with peeks and pokes, after testing an IO port write.

Something like...

1For TestAddr=C000 to EF00 Step 64k
2   For TestIoAddr=0 to 65535
3       For IoTestByte=0 to 255
4       Poke (TestAddr,"AA")
5       OUT TestIoAddr, IoTestByte
6       If NOT Peek (TestAddr) = "AA" Then
7          Print "Found EMS page op at Address: ", TestAddr, ", with IO byte ", IoTestByte, " at IO Address", TestIoAddr
8       Else
9       Endif
10      Next
11   Next
12Next

granted, this doesnt verify that there's RAM there first, but you should get the idea.

Naturally, you should exclude well known port addresses (220, 230, 250, 330, etc...) as well.

Just saying a relatively simple program can find out this info.

Predator99 wrote on 2019-01-26, 17:08:

😎 Same method, next card with 2 MB...:

I have seen this logo on the card somewhere before...anybody recognizes it? No other label on the card.

https://theretroweb.com/manufacturers/395

Card is added here:
https://theretroweb.com/expansioncards/s/tmc- … ix-megastar-mat

I have added the photos and info of several cards to TRW now. Feel free to throw in settings tables and/or any info that eventually shows up...

Suntek MEMOPLUS

SW1 corresponds exactly to the Settings of the SW2 of the DFI AT RAMBANK. For a System with 1 MB onboard you need i.e. a starting adress of 1.375M which is

SW1 ON ON OFF ON - OFF OFF OFF ON

SW2 is different:

DIP 2+3+4 set the EMS IO base adress:
ON OFF ON - 258h (0010 010 11000b)
ON ON ON - 218h (0010 000 11000b)
OFF ON OFF - 2B8h (0010 101 11000b)
...

DIP 5+6 sets the EMS/XMS RAM size (for 2 MB on the MEMOPLUS):
OFF OFF - 2 MB XMS, 0 MB EMS
ON OFF - 1.5 MB XMS, 0.5 MB EMS
OFF ON - 1 MB XMS, 1 MB EMS
OFF OFF - 0.5 MB XMS, 1.5 MB EMS = 96 pages
I didnt find a setting to allocate the whole 2 MB to EMS.

The EMS page frame seems to be fixed at CC00. Maybe it can be changed with DIP 7+8, but another setting didnt work. Maybe because space is allocated by XT-IDE.

Summarized, for a system with 1 MB onboard ond 2 MB on the MEMOPLUS use the follwoing settings:

To have 3 MB XMS in the system:
SW1 ON ON OFF ON - OFF OFF OFF ON
SW2 OFF ON OFF ON - ON ON ON ON

To have 1.5 MB XMS and 1.5 MB EMS using the RMS.SYS driver. Page frame at CC00, IO at 258h:
SW1 ON ON OFF ON - OFF OFF OFF ON
SW2 OFF ON OFF ON - OFF OFF ON ON

Great thread. I have two questions:

Situation: my 386sx mainboard allows 16mb max which is fully equipped.

Questions:
1. can I pass this limitation by an extension card?
2. (if not) would it be possible to provide and use 16mb xms via mainboard ram AND e.g. 16mb EMS provided by the extension card at the same time (via windowing or something)?

You see I hope that the 16mb limit is only valid for the simm slot memory of the mainboard.

Thanks

Marco wrote on 2025-12-03, 21:29:

Great thread. I have two questions: […]
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Great thread. I have two questions:

Situation: my 386sx mainboard allows 16mb max which is fully equipped.

Questions:
1. can I pass this limitation by an extension card?
2. (if not) would it be possible to provide and use 16mb xms via mainboard ram AND e.g. 16mb EMS provided by the extension card at the same time (via windowing or something)?

You see I hope that the 16mb limit is only valid for the simm slot memory of the mainboard.

Thanks

ISA expansion cards are limited to 16MB XMS address space and the ram will perform at like 1/6 the speed of 0 wait state 16MHz motherboard ram. So no, you cannot add additional XMS past 16MB. And no, it doesn't make any sense to install less memory on the main board just so you can run some over the ISA bus. The performance hit would be noticeable, even on a 386sx 16. It would be like going back to a slow 286 if you add 6+ wait states to your ram.

I have a 386sx that only supports up to 8MB on the motherboard. https://theretroweb.com/motherboards/s/formos … ustri-ub-320sai I tried an ISA ram card to take it to 16MB. https://theretroweb.com/expansioncards/s/accu … inc-rampat-plus I didn't have the best luck. The BIOS on the motherboard would only detect additional ram if I had less that 8MB on the motherboard, regardless of what SIMMs went where. And it was slow compared to main memory. So the Rampat card eventually went into an 6mhz 286 that only took 1MB on the board and it it did some real good and wasn't horribly slow compared to main memory. Made Windows 3.1 possible. And the 386sx? I stopped trying to run Win98se on my 386sx 16 because if I was looking for a crappy experience, I could have just as crappy an experience with 8MB on the motherboard as I could with 8 on the motherboard and an additional 8MB of slow RAM on the ISA bus. OS/2 2.0 was a better choice if I wanted to replicate my home computer from 1992. Crappy Win 3.1 was probably where I should have been. While I remember running OS/2 and being happy at the time when I upgraded to 8MB, I also remember upgrading my motherboard that year to a 486 w/ 16MB as soon as I could scrape together $750.

EMS is paged into a window below 16MB, so yes, there are EMS cards that can add up to 32MB of EMS but why? It's going to be slow and what are you going to use it for? Smart drive? It's going to be almost as slow as your disk drive. Lotus 123? Maybe just because you can I guess. Any apps or games that require EMS will work faster with EMM386 emulating the EMS in main memory than they will with an ISA EMS card. It's just that slow, even at 16Mhz.

Thank you for posting your experiences.

Why do I ask:

1. to increase my knowledge about the topic
2. my quite blank win95 installation reports 0kb available memory within winword / syteminfo (yes with cache etc) So I said: hm are there alternatives?!
3. reference to other quite current posts: in case these cards will (most probably) do MMIO they will always be faster than any hdd. Correction: from 286 ongoing no increase due to MMIO as stated in another thread

Regards

Great thread indeed.

I have 2 questions, the first one is regarding Marco's answer. Especially for 286 and 386's, I try very hard to stay in Real mode as much as possible. It is my understanding that staying is real mode is the fastest and most compatible experience for DOS programs. So using an hardware EMS card was making sense for me for UMB and EMS, since I can skip emm386 and the cpu can stay in Real mode, instead of the V8086 mode. If I understand correctly your message, even on a slow 386sx (16 or 25), Emm386 would be faster? It was my understanding that for slow CPU, EMS is the preferable way, as it is much faster than XMS. The only advantage would be to stay on Real mode for maximum compatibility?

The second question is regarding the main subject. I bought this EMS/XMS card on ebay (https://www.ebay.ca/itm/406321916604) and I hope that the floppy containing the driver is still readable, because I haven't found any driver for that card online. Does anyone know whether the SIIG Memoplus A.4 is a rebadge of some other manufacturer’s design, or it uses a specific driver? If the disk do work, I will upload the driver online for sure.

Thanks!

Good luck with the card and driver. Let us know what your experiences were.

I understand your realmode thoughts. I use an alternative memory driver that provides xms and upper memory on the vlsi scamp while remaining in realmode.

Unfortunately I have to tell you that each standard xms provider (himem or emm) will be faster using onboard ram than any Ems memory provided by an Isa card.

Anyway all the best with your tests.