This is very interesting.

So you're saying that adding a better graphics card and utilizing its higher colors and resolutions can actually make the 386 run SLOWER instead of having the GPU offload some of that demand from the CPU and onboard components. This is the opposite of the behavior I was expecting. But again, I'm not all that well-versed in how all this works, technically speaking.

I've actually experienced this phenomenon with this system already. Since switching to 256 colors, even sticking with 640x480, elements of Windows take longer to "draw" (if that term makes sense) and the Flying Windows screensaver runs laughably slow.

nezwick wrote on 2024-03-29, 00:49:

This is very interesting.

So you're saying that adding a better graphics card and utilizing its higher colors and resolutions can actually make the 386 run SLOWER instead of having the GPU offload some of that demand from the CPU and onboard components. This is the opposite of the behavior I was expecting. But again, I'm not all that well-versed in how all this works, technically speaking.

I've actually experienced this phenomenon with this system already. Since switching to 256 colors, even sticking with 640x480, elements of Windows take longer to "draw" (if that term makes sense) and the Flying Windows screensaver runs laughably slow.

I'm not as well versed as others in this era of graphics hardware, but I believe you'll need a graphics card that offers some kind of GUI acceleration in Windows as well as a driver to run it. Something like a CirrusLogic CL5429 with 1MB of memory is one that's probably worth looking for without costing an arm and a leg... but there are probably others that are better from S3, WD, Tseng, or possibly later Trident cards, etc. ... just make sure you look it up first to be sure it has the features you want. One digit difference in the model of a card can mean no\less GUI acceleration.

Finding a good "fast" ISA card for cheap is a roll of the dice however. And, as mentioned by others, "fast" is relative. ISA is... not good at high speed graphics, to say the least.

nezwick wrote on 2024-03-29, 00:49:

This is very interesting.

So you're saying that adding a better graphics card and utilizing its higher colors and resolutions can actually make the 386 run SLOWER instead of having the GPU offload some of that demand from the CPU and onboard components. This is the opposite of the behavior I was expecting. But again, I'm not all that well-versed in how all this works, technically speaking.

I've actually experienced this phenomenon with this system already. Since switching to 256 colors, even sticking with 640x480, elements of Windows take longer to "draw" (if that term makes sense) and the Flying Windows screensaver runs laughably slow.

A VGA or SVGA card, in the classical sense, is not a GPU and does not accelerate anything except drawing some 2D graphics primitives, copying stuff within graphics card memory and things like that.
Not all SVGA chips even offered this kind of acceleration. The early lower end ones, like the TVGA8900 had none .

This acceleration needs a graphics chip specific driver for the OS one is using (Windows, OS/2, etc ) and is not available to DOS programs, generally speaking (except some specialized stuff like CAD programs that have their own drivers).

Otherwise, an (S)VGA card is just a memory frame buffer whose content is displayed through a DAC to a monitor.

If a given card supports 8-bit color and 16-bit color at a given resolution, it will be faster in 8-bit color, simply because there is less data to move to it.

I general, an (S)VGA card can be slower or faster than another due to factors like :
- the type of BUS it uses (VLB and PCI cards are MUCH faster than ISA)
- how efficiently it handles bus transfers
- the clock speed, type and organization of its onboard memory
- the efficiency and design on the actual controller (and its clock speed)

nezwick wrote on 2024-03-28, 22:21:

So now I wonder, what type of graphics card do I need to get in order to get the normal 16- or 32-bit color modes in Windows? Was that a luxury back in those days that required an expensive high-end card?

The following ISA chipsets in my collection have been confirmed to have at least 16-bit colour support in Win 3.1:
* ATI Mach32
* Avance Logic ALG2101
* Cirrus Logic GD5429, GD5434
* Oak OTI087, OTI087X
* S3 P86C911, P86C924, P86C801, P86C928
* Tseng ET4000/W32i (this is not universal - my Hercules Dynamite has 16-bit colour support, but another card with 1MB of soldered RAM and no expansion can only support 8-bit output)
* Trident 8900D
* Weitek Power 5286
* Western Digital WD90C31

Additionally, the Oak OTI077 and Tseng ET4000 are capable of 16-bit colour but it depends on the RAMDAC - both of mine only support 8-bit output, while trying to use 16-bit colour on those causes incorrect colours. All Cirrus Logic GD542x except the GD5420 also have 16-bit output according to the GD5422 drivers, but I don't have anything except the GD5420 and GD5249 at the moment, though I should be receiving a 1MB GD5424 sometime this week to confirm whether it works or not. I've only tested the single driver for the ALG2101 that is compatible with the 286, and the lone 800x600 16-bit mode that is provided with that driver is not accelerated compared to the 8-bit modes - I'll need to check the later 386+ drivers at some point. The Realtek RTG3106 drivers also contain 16-bit modes, but my RTG3106 card that should also be coming this week has a Bt476 clone RAMDAC which only supports 8-bit output.

I should also note that the Weitek Power 5286 is using 5186 drivers as no drivers for the 5286 can be found, which causes heavy corruption in 8-bit modes and it doesn't appear that the 16-bit modes are accelerated, while the 16-colour modes definitely are.

I can confirm that Cirrus Logic GD5422 (and later) do support 16bpp, and even 24bpp.

In general, ISA cards have separate RAMDAC chips, and HiColor/TrueColor support depends on the RAMDAC type.
But the 54xx series is different - RAMDAC is already integrated.

nezwick wrote on 2024-03-19, 19:43:

The number on the chip is Acer M3125. I have found a few mentions of the card on the internet (and here at Vogons) but nowhere seems to have drivers for it.

Sorry for necro but this is a rare chip/card, and the only topic on Vogons, so why start another one. Do you still have that system? Can you dump the video BIOS for me? Software read should be enough, NSSI can do it. See if you can disable video ROM shadow in BIOS for that though, otherwise the dump might not be clean even if it passes the checksum test.

As for your questions (and why I'm looking for the BIOS) - I had a card with that chip back in the '90. It was branded AdPlus with stickers. I had to part ways with my old system but I bought another card based on M3125 some time ago. It's slow, although not as bad as Realtek RTG3105, and it works with +5V only and has a nice, clean output on modern LCD monitors. It's almost identical to what I remember but came with only 256k RAM. I populated the empty sockets but it turns out the BIOS is an earlier version, does not support the 512k SVGA modes properly.

IIRC the card came with 5.25" floppy (or two) and had drivers for some DOS software like CADs, Lotus, and Win 3.0. Even back then it was a bit obsolete set and I have hazy recollection of trying to force that 3.0 driver into Win 3.1/3.11 WfW and failing. But I didn't try very hard as I was somewhat spooked by the possibility of damaging the CRT monitor with bad sync signals. Sadly I no longer have any copies of these floppies, or the floppies themselves.

What I do have is perhaps of some use - my own VESA TSR. I even worked around the broken BIOS that I have and got the TSR to offer 800x600 256 color mode. The card itself can do 1024x768 but due to chip and RAMDAC limitations only in interlaced mode. Also the M3125 is a bit odd, it requires both memory segments (A000 and B000) to be used for SVGA, and switches banks as 128k chunks. Even though most DOS games that use SVGA are protected-mode and should have no issues with this, considering VESA standard allows it, it results in broken graphics on pretty much everything as the code seems to be limited to 64k sized banks for some reason. But there is at least one game that works correctly and that's Transport Tycoon series. I spent a LOT of time playing it on my otherwise slow 386DX.

EDIT: Actually, 2 games. Bugs! from Sierra can runs in 16 colors VGA, 640x480, but can also use 800x600 if it can swith to that mode. Since both are planar there is no need to switch banks, and 800x600 in 16 colors works with the TSR.

I can offer the VESA TSR in exchange for the BIOS dump 😜

Deunan wrote on 2025-06-11, 13:42:

Do you still have that system? Can you dump the video BIOS for me? Software read should be enough, NSSI can do it. See if you can disable video ROM shadow in BIOS for that though, otherwise the dump might not be clean even if it passes the checksum test.

Give me about a week to check into this. I moved a bunch of my old systems into storage temporarily while I repaint the room they were in. I THINK of the two Acer systems I got, I kept this one and sold the other, but honestly I can't remember which was which.

I've never dumped a video BIOS before, so I might need some assistance stepping through the process. But I'll let you know - if you don't hear back, feel free to remind me. The computer projects kind of go to the back of my mind during the summer when we're so busy with other stuff.