auron wrote on 2025-08-02, 11:05:

so according to that, should (could) using cards with VRAM/WRAM alleviate this issue? potentially SGRAM as well, although since it was optional on some cards its features may not necessarily have been used.

Palette comes from dedicated memory in the RAMDAC and has nothing to do with the memory that holds pixel data etc. so SGRAM vs SDRAM or any other memory type plays no role in here.
It is purely about the RAMDAC part of things and in majority of the designs there's just a small amount (256 x 18/24 bits) of SRAM in them. What will make the difference is how the SRAM is being utilized and if it is single or dual port.

I recall seeing some screenshots of this behaviour on various cards in the CRT Terminator related posts here on this forum. There are definitely a bunch of different behaviours across various cards.

darry wrote on 2025-08-02, 12:29:

The Diamond Stealth 2000 that OP has is based on a S3 Virge 325 with EDO RAM and a 135MHz integrated RAMDAC. I owned and used a […]
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auron wrote on 2025-08-02, 11:05:

duke3d is another good example of this, the health pickup and damage screen tint effects cause those snow effects on a lot of ca […]
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duke3d is another good example of this, the health pickup and damage screen tint effects cause those snow effects on a lot of cards.

Tiido wrote on 2025-07-29, 15:27:

Better option is to use dual ported memory but that is an expensive thing (in cost and also silicon realestate) and generally not done because of it.

so according to that, should (could) using cards with VRAM/WRAM alleviate this issue? potentially SGRAM as well, although since it was optional on some cards its features may not necessarily have been used.

comparing an s3 864/868 vs. 964/968 might be useful in this regard.

The Diamond Stealth 2000 that OP has is based on a S3 Virge 325 with EDO RAM and a 135MHz integrated RAMDAC. I owned and used a card base on that same chip back in the day and I was playing Duke Nukem 3D a lot, mostly, AFAICR, at 512x384 (using Dietmar Meschede's S3 VBE/Core 2.0 utility) and I do not recall seeing the effect that you mention on a 15" CRT. AFAICR, my card was clocked at 50 or 55MHz.

The ATI Rage Pro typically used SDRAM clocked at 75MHz, if I am not mistaken.

OP mentioned that the issue is more apparent on the Diamond Virge based card than on the ATI Rage Pro one. If the issue was purely related to memory bandwidth, I would have expected the opposite.

Actually, it’s the other way around: the Virge card shows much less or no artifacts at all depending on the game while the Rage Pro shows a lot of artifacts.
I also vaguely remember seeing the issue in some DOS games, too (warcraft 1 I guess?) so I don’t think its limited to windows games.
Would love to try duke nukem 3d to check if I get the snow effect on the Rage Pro but my main monitor just got busted and the colors are all messed up now. Have to wait for the replacement to arrive.
Edit: One of the threads here point out to a program called PALANIM to test exactly that. Surely will take a look once I get another monitor.
As for fixing it (under windows, at least) maybe If I try forcing vsync on the ATI card using powerstrip somehow?

auron wrote on 2025-08-02, 13:19:

i'm understanding OPs posts the other way around - his virge card seems to show the issue less than the rage pro in the games th […]
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darry wrote on 2025-08-02, 12:29:

OP mentioned that the issue is more apparent on the Diamond Virge based card than on the ATI Rage Pro one. If the issue was purely related to memory bandwidth, I would have expected the opposite.

i'm understanding OPs posts the other way around - his virge card seems to show the issue less than the rage pro in the games that he tested.

the other thing is that OP seems to be talking only about windows games, while duke3d is DOS. in DOS ati cards generally force vsync, which will make them less affected than nvidia cards that don't, for instance. according to the (hardly comprehensive) notes i made on this, the TNT2 with SGRAM shows the issue in duke3d while the voodoo3 with SDRAM doesn't. but the voodoo3 has similar looking but consistent snow issues in VGA games that have also been discussed in several threads here.

so although the effect can look similar in different games, there are a lot of other factors going on here.

I meant less. Going to edit my post. Thank you.

The Voodoo 3 snow issues I was having on an SDRAM based Voodoo 3 completely went away once I flashed the vBIOS to a different one.

Was able to test again, this time on another CRT monitor.
As expected, the snow effect is still there with the Ati Rage Pro but almost not noticeable using the S3 card. By running the PALANIM I could verify that the Rage Pro has lots of snowing effects on the whole screen, the effects go away once I press S to enable sync mode so I believe I finally got my answer on why the effect happens 😀
It seems there is nothing I can do and this is just how the card behaves so I'll just stick with the S3 card anyways... I'll lose the OpenGL and D3D acceleration but TBH I'm not missing much because the Ati card is still quite slow for giving decent 3D performance in 640x480 with this CPU, and reducing the resolution for D3D or OGL games does not improve much, in fact, running software mode on any resolution 400x300 or below is actually FASTER than using 3D acceleration in those same resolutions.

Btw, huge thanks to everyone who posted here.