VLB and 3.75MB of memory seems a bit unusual. Most VLB cards had 2MB and only a few had possibility of expanding to 4MB via daughter-boards (ATI Mach64, Diamond Stealth64 VRAM).

You could have some TiGA CAD VGA card. Those had some weird memory configurations:
http://www.vgamuseum.info/index.php/component … chitecture-tiga

POST screen in more than one colour wasn't that rare, so I'm afraid that won't be too conclusive.

As for the RAM, 3.75MB sounds very weird. If the amount is correct, this will almost certainly be a card with two separate chips, one for VGA, the other for the accelerator, but even there, 768kB for the one and 3MB for the other sounds unusual. The closest I'm aware of for VLB is the Orchid P9000/VLB, with a Weitek P9000 for accelerated SVGA with 2MB VRAM and a secondary Weitek VGA chip with 1MB DRAM for non-accelerated VGA. Or there's the Miro Crystal 24S, with S3 928 and 3MB VRAM. But those are both a round 3MB, so not the 3.75MB you're looking for...

Quote:
"The 1280 × 1024 resolution became popular because at 24 bit/px color depth it fit well into 4 megabytes of video RAM. At the time, memory was extremely expensive. Using 1280 × 1024 at 24-bit color depth allowed using 3.75 MB of video RAM, fitting nicely with VRAM chip sizes which were available at the time (4 MB): (1280 × 1024) px × 24 bit/px ÷ 8 bit/byte ÷ 2^20 byte/MB = 3.75 MB"

Maybe you remember of using 3.75mb, not actually having 3.75mb?

Any other detail about the card that you can remember?

I mean, there's not that many VLB cards around that had more than 2MB and were also around in the consumer space, S3 cards are the only ones that come to my mind, something like a Diamond Stealth 64 VLB or later Trio cards

Diamond cards had a blue stripe on top in the BIOS screen.

and while ET4000W32i/p support 4MB it seems like, I don't think there were many cards around that had the provision for anything more than 2MB (at least not in VLB)

I could be wrong about the 3.75Mb. But I think it was because I only had 7 extra ram chips fitted out of the possible 8.
The post screen showed the amount of Vram.

dionb wrote on 2021-11-25, 09:41:

POST screen in more than one colour wasn't that rare, so I'm afraid that won't be too conclusive.

As for the RAM, 3.75MB sounds very weird. If the amount is correct, this will almost certainly be a card with two separate chips, one for VGA, the other for the accelerator, but even there, 768kB for the one and 3MB for the other sounds unusual. The closest I'm aware of for VLB is the Orchid P9000/VLB, with a Weitek P9000 for accelerated SVGA with 2MB VRAM and a secondary Weitek VGA chip with 1MB DRAM for non-accelerated VGA. Or there's the Miro Crystal 24S, with S3 928 and 3MB VRAM. But those are both a round 3MB, so not the 3.75MB you're looking for...

It doesn't help the OP, but you are not right about the Miro Crystal 24S. That card is very peculiar by having 3.25MB of RAM. The "24" in the model number points to the primary focus of that card: Modes with 24 bits/pixel. This is why most of the banks on that card do only have 24 bit width. The top 8 bits of each 32-bit bank are not used in 24bpp modes. For VGA compatibility, the S3 928 needs the first bank to have the full 32 bit width, though. Thus the 24S has one bank of 256K x 32 (1MB) and three further banks of 256K x 24 (768KB), which results in a total of 3.25MB.

mkarcher wrote on 2021-11-25, 19:28:

[...]

It doesn't help the OP, but you are not right about the Miro Crystal 24S. That card is very peculiar by having 3.25MB of RAM. The "24" in the model number points to the primary focus of that card: Modes with 24 bits/pixel. This is why most of the banks on that card do only have 24 bit width. The top 8 bits of each 32-bit bank are not used in 24bpp modes. For VGA compatibility, the S3 928 needs the first bank to have the full 32 bit width, though. Thus the 24S has one bank of 256K x 32 (1MB) and three further banks of 256K x 24 (768KB), which results in a total of 3.25MB.

Makes it even weirder - and me blind. I have one and never noticed, just went with Miro's "3MB" promise.

dionb wrote on 2021-11-25, 22:31:

Makes it even weirder - and me blind. I have one and never noticed, just went with Miro's "3MB" promise.

That's actually fair advertising. The usable video memory in that card is either 1MB (in VGA compatible modes) or 3MB (in 24bpp modes). You don't get any mode where all the 3.25 MB are used at once. Just for reference, neither the 16S (I have one) nor the 32S have incomplete banks as the 24S does. The 16S has two banks of 1MB each and the 32S has four banks of 1MB each.
You need an even number of banks, because in high-color modes (and the high-performance 256 color modes), the MiroCrystal 16/24/32S design requires the use of bank interleaving. A card with three banks of 1MB wouldn't work.

The 24S likely performs less than stellar in 16 bit modes (if it supports them at all), because you can only use 16 bit per bank, which is one pixel per memory cycle, as in true color modes. The 16S and 32S can pack two 16-bit pixels into a single memory word (due to the bank width of 32 bits), enabling them to run at higher clocks and use the full RAM. On the 24S, I don't see a way to implement 16bpp without having 16 bits unused in framebuffer space after each 16-bit pixel, so good luck finding software supporting this scheme...
You likely can use the acellerator in one-pixel-per word 16bpp modes if you configure it for true color operation. You just need to set appropriate color values while drawing. Again, performance will suffer compared to two-pixels-per-word. Net effect: For 16bpp, the 2*1MB memory on the 16S is far superior to the 4*0.75MB of the 24S. Don't buy the 24S if you care about 16bpp modes. It's the wrong tool for that job.

here is a pic of the 24S, was it this the one?

keropi wrote on 2021-11-26, 10:31:

here is a pic of the 24S

I am surprised to find that the 24S has the colorimeter interface installed. It is missing on my 16S. Obviously I didn't research the series as well as I thought, as I expected this to be a premium feature of the 32S only. On the other hand, color calibration makes a lot of sense on a card optimized for 24bpp modes.

Have you ever seen the matching colorimeter? Did it ever exist?

mkarcher wrote on 2021-11-26, 12:28:

[...]
Have you ever seen the matching colorimeter? Did it ever exist?

nope, no idea... I got this card from dionb several years ago - maybe he has more info 😀
all I know is that this card is geared towards productivity - and I can't say I particularly like it for my needs 🤣

2.25mb was definitely a thing in the earlier days of expensive ram due to 1024x768 fitting nicely

A few laptops advertised that as well

3.75 I’ve never heard of 1280x1024 wouldn’t fit and would need the full 4mb

My ye olde Cornerstone B&W proprietary workstation monitor graphics card had 1.25mb but it had 2 heads 1mb for hi-res grayscale and the other for a secondary VGA color monitor.

———————///////
Thinking back 3.75mb may have been on a peculiar “Terminator 2” 3D graphics chipset scrapped out of some type of ancient 3D workstation that got scrapped by Allen Stober that was used for movies, I can no longer remember the brand/type of the system.

Ah well definitely wouldn’t be Pc related

rmay635703 wrote on 2021-11-26, 15:18:

2.25mb was definitely a thing in the earlier days of expensive ram due to 1024x768 fitting nicely […]
Show full quote

2.25mb was definitely a thing in the earlier days of expensive ram due to 1024x768 fitting nicely

A few laptops advertised that as well

3.75 I’ve never heard of 1280x1024 wouldn’t fit and would need the full 4mb

My ye olde Cornerstone B&W proprietary workstation monitor graphics card had 1.25mb but it had 2 heads 1mb for hi-res grayscale and the other for a secondary VGA color monitor.

———————///////
Thinking back 3.75mb may have been on a peculiar “Terminator 2” 3D graphics chipset scrapped out of some type of ancient 3D workstation that got scrapped by Allen Stober that was used for movies, I can no longer remember the brand/type of the system.

Ah well definitely wouldn’t be Pc related

Technically, you can run 1280x1024 with 16 colors on 1MB VRAM. Just referenced my Boca VL-Bus SuperX VGA (GD5429) manual. It all depends on the color palette. I think you need more like 8MB to do 1280x1024 at 16.8M colors.

HangarAte2nds! wrote on 2021-11-27, 04:35:

rmay635703 wrote on 2021-11-26, 15:18:

2.25mb was definitely a thing in the earlier days of expensive ram due to 1024x768 fitting nicely […]
Show full quote

2.25mb was definitely a thing in the earlier days of expensive ram due to 1024x768 fitting nicely

A few laptops advertised that as well

3.75 I’ve never heard of 1280x1024 wouldn’t fit and would need the full 4mb

My ye olde Cornerstone B&W proprietary workstation monitor graphics card had 1.25mb but it had 2 heads 1mb for hi-res grayscale and the other for a secondary VGA color monitor.

———————///////
Thinking back 3.75mb may have been on a peculiar “Terminator 2” 3D graphics chipset scrapped out of some type of ancient 3D workstation that got scrapped by Allen Stober that was used for movies, I can no longer remember the brand/type of the system.

Ah well definitely wouldn’t be Pc related

Technically, you can run 1280x1024 with 16 colors on 1MB VRAM. Just referenced my Boca VL-Bus SuperX VGA (GD5429) manual. It all depends on the color palette. I think you need more like 8MB to do 1280x1024 at 16.8M colors.

That’s not surprising since it only takes 640kb of VRAM to do. Theoretically could do 64 colors in that amount of vram

However There were literally cards with 2.25mb of ram specifically to support 1024x768x16m, the ET6000 came from the factory that way.

I also had an odd card with only 256k of vram that supported monochrome 1280x1024

My Cornerstone 1mb card advertised 1600x1280x256 grayscales on 1mb of vram
And indeed 256 color windows games ran and looked great in grayscales but they failed to mention that card dithered in hardware with localized pallets so everything ran quickly without extra cpu overhead.

mkarcher wrote on 2021-11-26, 12:28:

keropi wrote on 2021-11-26, 10:31:

here is a pic of the 24S

I am surprised to find that the 24S has the colorimeter interface installed. It is missing on my 16S. Obviously I didn't research the series as well as I thought, as I expected this to be a premium feature of the 32S only. On the other hand, color calibration makes a lot of sense on a card optimized for 24bpp modes.

Have you ever seen the matching colorimeter? Did it ever exist?

No not this one, it had plenty slots for VRAM expansion. Think it had on both sides of the card.