ISA graphics with high resolutions is like viewing images using a dial-up modem.

From my experience with later VRAM based cards, they perform more or less the same as their DRAM counterparts. I suspect that there was more truth to VRAM cards being slower in dos with the first generation of accelerators, but some kind of workaround was implemented in later products.
Then you have VRAM based cards like the Weitek P9x00. Maybe some people didn't realise the bottleneck was the crappy VGA chip, and not the VRAM.

Anonymous Coward wrote on 2026-04-21, 05:47:

ISA graphics with high resolutions is like viewing images using a dial-up modem.
...

True if you're talking about non-accelerated cards. But very wrong when using better chipsets like CL-GD5434, Mach32, Mach64.

Must be around 10 years now... I've played around with a 386DX-40 and Windows 95. It was upgraded to 486DLC-40, 32MB RAM, CF card and Ati Mach64 4MB VRAM ISA. For the usual Windows operation it was very snappy. Of course it was slow where the CPU power was lacking. But GUI was very responsive. So no slideshow 😉

Ok, let's say I was willing to settle for a 1MB card for the time being, that can do 1024x768 at 256 or 800x600 at 16-bit or 640x480 at 24-bit.

What 1MB ISA card would you recommend that has decent 2D acceleration? One that is relatively easy to find and affordable. From the CL-GD542X line, only the CL-GD5428 and CL-GD5429 have 2D acceleration and they're not particularly affordable.

And how important is 2D acceleration for 1MB cards? Is it okay to drive 1024x768 at 256 colors without BitBLT over ISA? For Windows 9x and mid-90s Windows games, does 2D acceleration even make a difference? I've never seen benchmarks comparing 2D performance for games across video cards honestly.

Finally, a stupid question but if I set 1024x768 @ 256 colors in Windows, and then I play a game that can do 640x480 @ 16-bit, will it automatically switch to the higher color depth? Or do I have to lower the resolution/increase color depth in Windows first? Realistically, very few games that even the most powerful 486 can play will be capable of 16-bit color, but I'm curious.

Qbccd wrote on 2026-04-21, 09:35:

Finally, a stupid question but if I set 1024x768 @ 256 colors in Windows, and then I play a game that can do 640x480 @ 16-bit, will it automatically switch to the higher color depth? Or do I have to lower the resolution/increase color depth in Windows first? Realistically, very few games that even the most powerful 486 can play will be capable of 16-bit color, but I'm curious.

Depends on what graphics interface the game is using and how it's programmed. Some will complain and not work. Some will complain and continue in the wrong graphics mode causing visual issues. Some will auto switch and leave your desktop at the new mode after you exit. Some will auto switch when opening and auto switch when you exit.

Some more options:
The ELSA Winner 1280 is a C&T based addon card like the above mentioned TIGA boards.
The ELSA Winner 1000/2000 an S3 based ISA/EISA combo board upgradeble to 2MB but need ZIP RAM
The Spea Mercury (pro) is a S3 based standalone board (probably sold under Diamond, v7 or different brands as well)
The ATI might be the most common board for HR graphics on ISA.

Accelerated high res operations over isa will be fast, regardless of resolution and depth.

Bitmap transfers, on the other hand, is bottlenecked by bus speed and gets more and more worse the higher the resolution and bit depth.

Isa cards are for gaming at 320x200.

You can work a spreadsheet or a document at high res mode in gui.

Qbccd wrote on 2026-04-20, 21:52:

Yeah... Maybe I'll just get a CL-GD542x for now, and I can periodically look for deals on the GD5434. Where was that auction that you referenced, Ebay?

The auction was on ebay. Often labelled "speedstar 64" and other names that are written on the card.

Qbccd wrote on 2026-04-21, 09:35:

What 1MB ISA card would you recommend that has decent 2D acceleration? One that is relatively easy to find and affordable. From the CL-GD542X line, only the CL-GD5428 and CL-GD5429 have 2D acceleration and they're not particularly affordable.

And how important is 2D acceleration for 1MB cards? Is it okay to drive 1024x768 at 256 colors without BitBLT over ISA? For Windows 9x and mid-90s Windows games, does 2D acceleration even make a difference? I've never seen benchmarks comparing 2D performance for games across video cards honestly.

Finally, a stupid question but if I set 1024x768 @ 256 colors in Windows, and then I play a game that can do 640x480 @ 16-bit, will it automatically switch to the higher color depth? Or do I have to lower the resolution/increase color depth in Windows first? Realistically, very few games that even the most powerful 486 can play will be capable of 16-bit color, but I'm curious.

For 1MB cards, the Chips F65545 and the WD90c33 are better then the CL GD5429. The F65545 is the most available. On ebay: "advantech pca 6653".

The lowest cost 1MB ISA card with BitBLT is the WD90C31. It's in the realm of the GD5428/GD5429.

Everything will be a slideshow without BitBLT.

Resolution & colour depths switch. Most games only use 256 colours for speed.

Some 1MB cards can use the Vesa LFB mode and can run higher resolution in Dos (320x400, instead of 320x200).

MikeSG wrote on 2026-04-21, 13:31:

The auction was on ebay. Often labelled "speedstar 64" and other names that are written on the card. […]
Show full quote

Qbccd wrote on 2026-04-20, 21:52:

Yeah... Maybe I'll just get a CL-GD542x for now, and I can periodically look for deals on the GD5434. Where was that auction that you referenced, Ebay?

The auction was on ebay. Often labelled "speedstar 64" and other names that are written on the card.

Qbccd wrote on 2026-04-21, 09:35:

What 1MB ISA card would you recommend that has decent 2D acceleration? One that is relatively easy to find and affordable. From the CL-GD542X line, only the CL-GD5428 and CL-GD5429 have 2D acceleration and they're not particularly affordable.

And how important is 2D acceleration for 1MB cards? Is it okay to drive 1024x768 at 256 colors without BitBLT over ISA? For Windows 9x and mid-90s Windows games, does 2D acceleration even make a difference? I've never seen benchmarks comparing 2D performance for games across video cards honestly.

Finally, a stupid question but if I set 1024x768 @ 256 colors in Windows, and then I play a game that can do 640x480 @ 16-bit, will it automatically switch to the higher color depth? Or do I have to lower the resolution/increase color depth in Windows first? Realistically, very few games that even the most powerful 486 can play will be capable of 16-bit color, but I'm curious.

For 1MB cards, the Chips F65545 and the WD90c33 are better then the CL GD5429. The F65545 is the most available. On ebay: "advantech pca 6653".

The lowest cost 1MB ISA card with BitBLT is the WD90C31. It's in the realm of the GD5428/GD5429.

Everything will be a slideshow without BitBLT.

Resolution & colour depths switch. Most games only use 256 colours for speed.

Some 1MB cards can use the Vesa LFB mode and can run higher resolution in Dos (320x400, instead of 320x200).

Thanks for the information. The WD90C31 looks good. But if I can get a Speedstar 64 for about $150, I'll wait for that. I'm definitely not in any hurry. Auction is definitely the way to go, just gotta get lucky.

Who knew building a retro PC cost as much as building a modern PC. I guess all you guys did.

Has this been suggested? - EXCELGRAPH - ISA Video Display Controller (ET4000/W32i)

Qbccd wrote on 2026-04-21, 09:35:

From the CL-GD542X line, only the CL-GD5428 and CL-GD5429 have 2D acceleration and they're not particularly affordable.

Thats's inaccurate. The first GD542x card with 2D acceleration is the 5426. While the family data sheet claims that the 5248 has an "enhanced" accelerator, I fail to find significant differences, so I guess they just optimized the performance. The acceleration functionality of the 542x family is quite basic, but covers the most important functionality for Windows 3.1, and especially for ISA, the Cirrus chips might provide good value. On VL, they should be considered low-end in my oppinion.

mkarcher wrote on 2026-04-21, 18:20:

Qbccd wrote on 2026-04-21, 09:35:

From the CL-GD542X line, only the CL-GD5428 and CL-GD5429 have 2D acceleration and they're not particularly affordable.

Thats's inaccurate. The first GD542x card with 2D acceleration is the 5426. While the family data sheet claims that the 5248 has an "enhanced" accelerator, I fail to find significant differences, so I guess they just optimized the performance. The acceleration functionality of the 542x family is quite basic, but covers the most important functionality for Windows 3.1, and especially for ISA, the Cirrus chips might provide good value. On VL, they should be considered low-end in my oppinion.

Ok, so it's GD5434 or bust then.

Full screen redraws and bitmap performance is going to suffer over the ISA bus, even with acceleration.

Wordprocessing and primitive line drawing performance would be acceptable with acceleration over ISA.

Many of the good 1MB cards with accelerated graphics were older designs that did not support higher colour depths.
Anyone know if the S3 928 takes a big performance hit when only 1MB is installed?

Anonymous Coward wrote on 2026-04-22, 06:04:

Many of the good 1MB cards with accelerated graphics were older designs that did not support higher colour depths.
Anyone know if the S3 928 takes a big performance hit when only 1MB is installed?

If the S3 928 is used in a straight-forward configuration, it has 32-bit data path from the accelerator to the video RAM for drawing purposes, and a second 32-bit data path from the second port of the VRAM for display purposes. This path can either go directly into a high-performance DAC with 32-bit data input, or it can be handled by the S3 chip and send through a legacy 8-bit data port to the DAC. A card designed that way does not take a performance hit if only 1MB is installed, as the only bank configuration of the 928 is 1MB per 32-bit bank. Adding extra banks does not increase performance.

The S3 928 does offer a special operating mode for high-performance cards (where "high performance" refers to the displaying part, not the drawing part, that is it enables higher resolutions / refresh rates), in which the data path between the RAM and the DAC is 64 bits wide. This can either be used with a DAC that has a 64-bit wide input, or you can multiplex the 64-bit VRAM output into 2*32 bits on the DAC input, allowing higher DAC input frequencies than the VRAM provides as output frequency. S3 calls this operating mode "parallel addressing". For the display data path, the implications of that mode are obvious: You get twice the width and thus twice the bandwidth. As the S3 chip is not involved in transferring pixels from the VRAM to the DAC in these high-performance modes (only for legacy VGA modes), coping with twice the bandwidth is entirely left to the card designer, and the 928 has no bottlenecks that prevent "twice the bandwidth" from being used. Using this mode also means that drawing (which only has a 32-bit data path) needs to be performed accordingly, which essentially uses the same access pattern as bank interleaving. The datasheet does not contain any hints that the S3 chip has increased bandwidth for drawing due to the interleaving nature, but it also explicitly states that it does not gain a drawing speed advantage in that mode. I'd assume the drawing engine is already running at maximum performance without bank interleaving, so the accelerator-side interleaving is just for allowing the 64-bit pixel data path, not for better drawing performance.

The choice between a 32-bit and a 64-bit display path is fixed in hardware. There are cards that use a 64-bit pixel data path, e.g. the miroCrystal 16S, 24S and 32S cards, but you can not find those cards with just 1MB of RAM. So even if the "parallel âddressing" mode does provide performance advantages (which I doubt, as I said), you can not profit of those advantages by upgrading a 32-bit card from 1MB to 2MB.

On 24-Aug-2019 I got a 1MB new & unused boxed Orchid Kelvin 64 ISA 64-bit graphics card which is GD5434 based for GBP 100 then upgraded it to 2MB. I just tried it and it supports the following resolutions on Windows NT V4.00 SP6a.

I used to have the same card back in the 1990s, suspect I binned it!, felt I would like one so as I recall I added an eBay search and after a few months one popped up. It cost more than I was expecting, but these days they seem to sell for way more and wonder "did I get a bargain"?

mkarcher wrote on 2026-04-22, 06:47:

If the S3 928 is used in a straight-forward configuration, it has 32-bit data path from the accelerator to the video RAM for dra […]
Show full quote

Anonymous Coward wrote on 2026-04-22, 06:04:

Many of the good 1MB cards with accelerated graphics were older designs that did not support higher colour depths.
Anyone know if the S3 928 takes a big performance hit when only 1MB is installed?

If the S3 928 is used in a straight-forward configuration, it has 32-bit data path from the accelerator to the video RAM for drawing purposes, and a second 32-bit data path from the second port of the VRAM for display purposes. This path can either go directly into a high-performance DAC with 32-bit data input, or it can be handled by the S3 chip and send through a legacy 8-bit data port to the DAC. A card designed that way does not take a performance hit if only 1MB is installed, as the only bank configuration of the 928 is 1MB per 32-bit bank. Adding extra banks does not increase performance.

The S3 928 does offer a special operating mode for high-performance cards (where "high performance" refers to the displaying part, not the drawing part, that is it enables higher resolutions / refresh rates), in which the data path between the RAM and the DAC is 64 bits wide. This can either be used with a DAC that has a 64-bit wide input, or you can multiplex the 64-bit VRAM output into 2*32 bits on the DAC input, allowing higher DAC input frequencies than the VRAM provides as output frequency. S3 calls this operating mode "parallel addressing". For the display data path, the implications of that mode are obvious: You get twice the width and thus twice the bandwidth. As the S3 chip is not involved in transferring pixels from the VRAM to the DAC in these high-performance modes (only for legacy VGA modes), coping with twice the bandwidth is entirely left to the card designer, and the 928 has no bottlenecks that prevent "twice the bandwidth" from being used. Using this mode also means that drawing (which only has a 32-bit data path) needs to be performed accordingly, which essentially uses the same access pattern as bank interleaving. The datasheet does not contain any hints that the S3 chip has increased bandwidth for drawing due to the interleaving nature, but it also explicitly states that it does not gain a drawing speed advantage in that mode. I'd assume the drawing engine is already running at maximum performance without bank interleaving, so the accelerator-side interleaving is just for allowing the 64-bit pixel data path, not for better drawing performance.

The choice between a 32-bit and a 64-bit display path is fixed in hardware. There are cards that use a 64-bit pixel data path, e.g. the miroCrystal 16S, 24S and 32S cards, but you can not find those cards with just 1MB of RAM. So even if the "parallel âddressing" mode does provide performance advantages (which I doubt, as I said), you can not profit of those advantages by upgrading a 32-bit card from 1MB to 2MB.

I tested briefly a Number Nine GXE (S3 928, 2MB VRAM) with a 64-bit DAC, and it flew in high colour mode.

VRAM cards are specifically for high res x high colour.