Could have something to do with the old monitor ID system vs the newer DDC system. ?

the answer to your question in full details is here:

Re: Help anyone with IBM PS2 and XGA card on MCA bus

55SX is known notoriously for that - it doesn't support disabling the on-board VGA. [EDIT] So, in other words - for PS/2 with 16-bit MCA bus, the minimum required for XGA is 56SX and up.

BTW, if you're in Europe and want to play with XGA/XGA-2, as cheaply as possible - you can do like I did - buy 56SX motherboard (that's model '8556' as numbers) - I see one is still available from the European seller from which I bought mine (around 50 EUR), then wire yourself PC floppy for initial setup:

Re: Help IBM PS/2 model 8556 wiring 1.44MB floppy

make yourself ATX to PS/2 adapter to use any modern ATX Power supply:

Re: Help IBM PS/2 model 8556 wiring 1.44MB floppy

and you're more or less set... and at the end I even found locally scrapped an original case for that with broken power supply and floppy, etc. but missing motherboard for just 20 EUR. So, my total build was very cheap, less than 3 digits. [EDIT] and i see your card is XGA-1, but now there is another supplier in Europe I know that has stock of over 50 pieces of XGA-2 cards, i.e. they are cheap now, as I mentioned here:

Re: Some questions about IBM PS/2 Models

saying it's the best time to buy XGA-2 if you want one.

On the NARKIVE for comp.sys.ibm.ps2.hardware i found this:

"Installing an XGA-2 (BVE adapter) in a Model 55SX is intended for a dual monitor configuration. The on-planar VGA is not disabled by the XGA-2's BIOS during POST, so its port will only display the XGA/XGA-2 high resolution modes (e.g. Windows and its drivers). Its VGA functionality is disabled in this configuration.
An AVE adapter (e.g. 8514/A) is needed for combined VGA and high-resolution modes from a single monitor."

Jinxter wrote on 2023-10-22, 19:23:

On the NARKIVE for comp.sys.ibm.ps2.hardware i found this:

"Installing an XGA-2 (BVE adapter) in a Model 55SX is intended for a dual monitor configuration. The on-planar VGA is not disabled by the XGA-2's BIOS during POST, so its port will only display the XGA/XGA-2 high resolution modes (e.g. Windows and its drivers). Its VGA functionality is disabled in this configuration.

exactly, and it's crazy inconvenient setup requiring 2 monitors, basically during boot and while you're running DOS, the video output is going via the on-boards VGA, then if you run Windows or any DOS software that initializes any of the XGA high resolution mode, the monitor attached to the on-board VGA goes black and the other one attached to the XGA card lights up with showing a picture and so on - every time going from low-res to high-res the picture is boucing between the 2 monitors.

Jinxter wrote on 2023-10-22, 19:23:

An AVE adapter (e.g. 8514/A) is needed for combined VGA and high-resolution modes from a single monitor."

or in other words (and not mambo-jumbo words of the IBM marketing department), the really supported cards on that PS/2 model without any weirdness is the 8514A adapter:

https://www.ardent-tool.com/video/8514.html

and not XGA/XGA-2 ... that's because the 3rd MCA slot has extra pins that can route the picture from the on-board VGA to the output of the 8514A adapter. So, still the on-board VGA is always fully enabled even in this case, but just its picture is routed to the output of the 8514A adapter.

mattw wrote on 2023-10-22, 19:31:

or in other words (and not mambo-jumbo words of the IBM marketing department), the really supported cards on that PS/2 model without any weirdness is the 8514A adapter:

I have an 8514A (two to be precise), but its not room i slot 3 due to an Dallas mod for coin battery - but that can be remedied.
The 8514A has bit block transfer in hardware. Will any games like GODS be faster by using 8514A instead of onboard VGA? Or are we only talking faster for apps that has a driver for the card?

Jinxter wrote on 2023-10-22, 19:48:

I have an 8514A (two to be precise)

you're lucky to have IBM 8514A adapters, because now they are extremely expensive many times the price of XGA card. that's why when I want to use 8514A, I am doing it on PC using PCI card - ATI Mach32 (their previous ISA cards like Mach8 are also 8514A compatible) which is full 8514A-clone and it can run all the software that requires 8514A.

Jinxter wrote on 2023-10-22, 19:48:

The 8514A has bit block transfer in hardware.

yep, no DMA with 8514A, DMA was one of the new features and improvements with XGA.

Jinxter wrote on 2023-10-22, 19:48:

Will any games like GODS be faster by using 8514A instead of onboard VGA? Or are we only talking faster for apps that has a driver for the card?

8514A cannot give you any benefits for games. In fact there is only 1 known game with 8514A Acceleration, AFAIK and that's:

https://www.classicdosgames.com/game/Mah_Jongg_-8514-.html

So, I would say for Games, 8514A is close to totally useless.

mattw wrote on 2023-10-22, 19:55:

Jinxter wrote on 2023-10-22, 19:48:

The 8514A has bit block transfer in hardware.

yep, no DMA with 8514A, DMA was one of the new features and improvements with XGA.

Not DMA but a blitter.
According to wikipedia https://en.wikipedia.org/wiki/Blitter
The IBM 8514/A display adapter, introduced with the IBM Personal System/2 computers in April 1987, includes bit block transfer hardware.
And this Video from PCRetroTech: https://www.youtube.com/watch?v=xrOci-LaMeo

So i was hoping that maybe the blitter would help in DOS games.

Jinxter wrote on 2023-10-22, 20:01:

According to wikipedia https://en.wikipedia.org/wiki/Blitter The IBM 8514/A display adapter, introduced with the IBM Personal S […]
Show full quote

According to wikipedia https://en.wikipedia.org/wiki/Blitter
The IBM 8514/A display adapter, introduced with the IBM Personal System/2 computers in April 1987, includes bit block transfer hardware.
And this Video from PCRetroTech: https://www.youtube.com/watch?v=xrOci-LaMeo

So i was hoping that maybe the blitter would help in DOS games.

the software cannot use any of the 8514A-features if it's not specifically programmed for 8514A. So, let me give you an Analogy: 8514A was for 2D acceleration, exactly what Voodoo was for 3D acceleration. That's why the same how you connect your Voodoo card with external cable to your VGA card (what they called "external pass-through"), 8514A is connected to the VGA cards, but internally - via those extra pins on the MCA slot. So, the same way as a Game needs to use GLIDE API to take advantage of the Voodoo card 3D acceleration, the software needs to use the IBM AI (Adapter Interface) API to take advantage of the 8514A card 2D acceleration. [EDIT] So, if you want to do some 2D Graphics programming like the guy from the Youtube video you posted then 8514A is pretty cool even in 2023.

mattw wrote on 2023-10-22, 20:15:

So, let me give you an Analogy: 8514A was for 2D acceleration, what was Voodoo for 3D acceleration.

Thank you, I think i understand now. Thanks for your help.
But would that same analogy work for XGA - in a computer where on-planar VGA is disabled, and taken over by the XGA?

Are there any demos/programs/stuff out there using the 8514A? Except for Windows, AutoCad and OS/2 drivers.

Jinxter wrote on 2023-10-22, 20:24:

Thank you, I think i understand now. Thanks for your help.

no problem at all, I like both 8514A and XGA as important technological step forwards. After all, the all mighty now ATi (acquired by AMD) started as cloning the IBM 8514A card.

Jinxter wrote on 2023-10-22, 20:24:

But would that same analogy work for XGA - in a computer where on-planar VGA is disabled, and taken over by the XGA?

no and the reason is you said it "planar VGA is disabled", i.e. XGA doesn't need an external VGA card to work, the same like modern 3D Graphics card is not like Voodoo and it doesn't need external cable to connect it to a VGA card. of course, to take advantage of the extra XGA features on top of the standard VGA you need to use the special IBM AI API (like for modern 3D GPU you need to use OpenGL or Vulkan or whatever API for the 3D), but still you can use XGA as (probably faster than the on-board one) VGA card.

Jinxter wrote on 2023-10-22, 20:24:

Are there any demos/programs/stuff out there using the 8514A? Except for Windows, AutoCad and OS/2 drivers.

'Fractint' for DOS:

https://en.wikipedia.org/wiki/Fractint

can use 8514A acceleration, but for XGA there is one interesting IBM demo "IBM XGA-2 Butterfly Demo with New Graphic Images", it's available on Vetusware website for example. your XGA card from the 1st picture is XGA-1 and I am not sure if it will run. also, I read a program called "TGRAF" for DOS can use 8514/A, but I've never seen that program - I don't even know what is doing.

mattw wrote on 2023-10-22, 20:39:

..but for XGA there is one interesting IBM demo "IBM XGA-2 Butterfly Demo with New Graphic Images", it's available on Vetusware website for example. your XGA card from the 1st picture is XGA-1 and I am not sure if it will run. also, I read a program called "TGRAF" for DOS can use 8514/A, but I've never seen that program - I don't even know what is doing.

I downloaded the demo and ran it successfully on my IBM Modell 55SX with XGA in slot 2.
Here is a video: https://www.youtube.com/watch?v=bUR0JdwmguY
I also made my own zip file of the demo, for easier installation. Check out the readme.txt for info on how to use. https://drive.google.com/file/d/1nbcH5nxfLR4m … -hor8LJqTZsmRSn