VOGONS


First post, by sndtst

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I have a Cirrus Logic CL-GD5428 2 MB VLB Video Card in a 486 DX2 66 but for some reason when I set the video mode to 256 or 65,356 colors I get this strange artifact. The small lines disappear if the color depth is set to 16 or 16 million colors. Anyone have any ideas what is causing this?

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Reply 1 of 8, by sndtst

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Here is the same video card working with 16 and 16 million colors

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Reply 2 of 8, by mkarcher

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My guess is that only 256-color and 16-bit color modes are accelerated using the out-of-the-box windows drivers (proper true color acceleration isn't implemented in the 542x series), and the problem is related to memory access patterns used by the accelerator.

Reply 4 of 8, by sndtst

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Tried it with 640x480 8bpp testing full VRAM reliability and it didn't report any errors. I also tested the speed in case the error is showing up in some other way, though I don't know the values I should be expecting. I suppose my next step will be to try a different video card version.

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Reply 5 of 8, by BitWrangler

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Back in the day it seemed some driver versions did that with some implementations. Meaning, try other drivers until it doesn't do that.

edit: they also liked to do that when they were too hot and/or didn't like the bus speed set, but I'm assuming you're at 33 0ws here, if it was DX2-80 I'd suggest setting 1WS... could be a plan at 33 if you've got a VLB i/o card there, some of them don't play nice.

Last edited by BitWrangler on 2022-03-01, 22:33. Edited 1 time in total.

Unicorn herding operations are proceeding, but all the totes of hens teeth and barrels of rocking horse poop give them plenty of hiding spots.

Reply 6 of 8, by BinaryDemon

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Just confirming, you have tested dos games at some of those resolutions and don’t see any issues right?

Check out DOSBox Distro:

https://sites.google.com/site/dosboxdistro/ [*]

a lightweight Linux distro (tinycore) which boots off a usb flash drive and goes straight to DOSBox.

Make your dos retrogaming experience portable!

Reply 7 of 8, by sndtst

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Just tested Duke 3D in SVGA 640x480 mode and while slow (it's only a 486) it seems clean.

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A Sound Test for as many games as I can find at SNDTST.com

Reply 8 of 8, by sndtst

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It seems the CL win3.1 drivers all have the video issues. But I just tried the generic Super VGA driver and 256 colors at 640x480 is working great (tried it with a CD-ROM that has video, In The 1st Degree, and the playback speed seemed smooth so I don't think I'm missing out on any performance with the intended drivers.

A Sound Test for as many games as I can find at SNDTST.com