VOGONS


First post, by DoomGuy II

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I may have mentioned this in another topic, but here it goes.

I have a custom generic AMD K6-2 PC with an ASUS P5A motherboard and a Voodoo 3 3000 video card installed. Did DOS and Windows games wonderfully. The only exceptions are that Terminal Velocity has that fuzzy effect going on in the 3D Realms logo and main menu (video here) (and yes I was using a CRT), and that the Windows version of Need for Speed SE will just refuse to run at all unless video acceleration is turned off. (Info found here.) Are there any fixes to these? Already tried vesafix, vbe15bpp, and vbehz with no results and I really don't want to go back and forth with the video acceleration in Windows.

Official Website: https://dg410.duckdns.org/

Reply 3 of 19, by jwt27

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Didn't see your video before, sorry. The fuzzy "snow" effect you're seeing is normal behaviour for Voodoo3, AFAIK.
If you enable write-combining cache (on PPro+ platforms) it usually gets worse, so maybe you can eliminate it by disabling video RAM cache altogether in the BIOS settings. This will likely cripple your frame rates though.

Reply 4 of 19, by PhilsComputerLab

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I had these small horizontal lines in some games when cloning VGA and DVI in DOS on a GeForce.

Check your monitor, is the game running at 70 Hz or 60? The CRT should have an info button.

Anything else "unusual" about your setup?

EDIT: Just test it. Zero issues. I don't get the glitches in your video, sorry.

I have the GOG version and ran it without sound.

Machine is a fast Slot 1 Pentium 3 1.1 GHz on a BX440 chipset board, 256 MB Ram, V3 3500 AGP, Turtle Beach Montego II and Windows 98 SE. I ran TV in MS-DOS mode.

PS: No it's not normal behaviour 🤣

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Reply 5 of 19, by DoomGuy II

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jwt27 wrote:

Didn't see your video before, sorry. The fuzzy "snow" effect you're seeing is normal behaviour for Voodoo3, AFAIK.
If you enable write-combining cache (on PPro+ platforms) it usually gets worse, so maybe you can eliminate it by disabling video RAM cache altogether in the BIOS settings. This will likely cripple your frame rates though.

Can't seem to find that option in the BIOS settings unfortunately. Any way to disable it on the fly?

philscomputerlab wrote:
Just test it. Zero issues. I don't get the glitches in your video, sorry. […]
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Just test it. Zero issues. I don't get the glitches in your video, sorry.

I have the GOG version and ran it without sound.

Machine is a fast Slot 1 Pentium 3 1.1 GHz on a BX440 chipset board, 256 MB Ram, V3 3500 AGP, Turtle Beach Montego II and Windows 98 SE. I ran TV in MS-DOS mode.

PS: No it's not normal behaviour 🤣

Well dang. I'm also using the GOG version and I'm getting these glitches.

Official Website: https://dg410.duckdns.org/

Reply 6 of 19, by jwt27

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DoomGuy II wrote:
jwt27 wrote:

Didn't see your video before, sorry. The fuzzy "snow" effect you're seeing is normal behaviour for Voodoo3, AFAIK.
If you enable write-combining cache (on PPro+ platforms) it usually gets worse, so maybe you can eliminate it by disabling video RAM cache altogether in the BIOS settings. This will likely cripple your frame rates though.

Can't seem to find that option in the BIOS settings unfortunately. Any way to disable it on the fly?

Not that I know of, unless your CPU supports MTRRs...

Reply 7 of 19, by elianda

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If his unspecified K6-2 is a CXT or later then it supports MTRRs.

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Reply 8 of 19, by DoomGuy II

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Just checked the settings for my CPU in WCPUID and found that it doesn't support MTRRs. Dang it! ...So much for disabling video RAM cache on the fly I guess. 🙁

Official Website: https://dg410.duckdns.org/

Reply 9 of 19, by kixs

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You're looking for "Video ROM shadow" in the BIOS. Even newer systems have it. But I'm not sure if this will solve the problem.

Requests are also possible... /msg kixs

Reply 11 of 19, by jwt27

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"Video ROM shadow" only copies the video BIOS from ROM to RAM for faster operation of BIOS functions. "Video RAM cacheable" allows the VGA memory (segment A000-AFFF) to be cached on the cpu's L2 cache, which speeds up access to this part of memory.

But then I don't know exactly how this works. If this option only sets MTRRs it wouldn't have any effect on pre-PPro cpus anyway.

edit: just did a quick test (Compaq Voodoo3 3500)
With write-combining cache enabled, I get this "snow" effect all over the logo screens and menu. Doesn't appear in-game.
With write-through caching, there's no snow at all. Same with uncached.
In write-back caching, the game fails to load and hangs on a black screen.

Reply 12 of 19, by DoomGuy II

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jwt27 wrote:
just did a quick test (Compaq Voodoo3 3500) With write-combining cache enabled, I get this "snow" effect all over the logo scree […]
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just did a quick test (Compaq Voodoo3 3500)
With write-combining cache enabled, I get this "snow" effect all over the logo screens and menu. Doesn't appear in-game.
With write-through caching, there's no snow at all. Same with uncached.
In write-back caching, the game fails to load and hangs on a black screen.

I see. So, how would I go about setting it to write-through mode or uncached mode, if there is a way?

EDIT: Nevermind. I've actually been fiddling with any settings that would have something to do with either the CPU or the graphics card. Disabled Frame Buffer Posted Write in BIOS settings and it worked. No "snow" effect in logos and menus at all.

Official Website: https://dg410.duckdns.org/

Reply 13 of 19, by 5u3

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The BIOS option for enabling/disabling write combining for the VGA range on P5A is called "Frame Buffer Posted Write" (what a stupid name) and can be found in "Chipset Features Setup".

[edit: DoomGuy II already has found the setting, it seems 😉]

Curiously, my Voodoo3 3000 AGP does not show these artifacts at all, but my Voodoo5 AGP does. I wonder if this has to do with failing components on the card...

Reply 14 of 19, by DoomGuy II

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Alright. So, now I know what's causing the system to show the "snow" effect in Terminal Velocity with the Voodoo 3 installed, which is the Frame Buffer Posted Write. The problem is I can only disable it from the BIOS, as it also cripples my frame rate a bit AFAIK, and I need to find a way to disable it on the fly.

In the meantime, I am still finding ways to get the Windows version of Need for Speed SE working and I don't know what to do.

Official Website: https://dg410.duckdns.org/

Reply 15 of 19, by 5u3

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DoomGuy II wrote:

The problem is I can only disable it from the BIOS, as it also cripples my frame rate a bit AFAIK, and I need to find a way to disable it on the fly.

jwt27 probably used MTRRLFBE, which is a neat utility, but unfortunately it doesn't work on my K6-3+. It might be worth a try though.

Other MTRR tools exist for K6, but these only handle LFB ranges and none of them allows you to turn write combining off.

Reply 16 of 19, by DoomGuy II

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Just tried the MTRRLFBE tool. Seems that I'm unable to change the VGA cache with this one. Keep getting the error:

MTRR setting failed: -8
MTRRs are not supported.

Official Website: https://dg410.duckdns.org/

Reply 17 of 19, by 5u3

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DoomGuy II wrote:

Just tried the MTRRLFBE tool. Seems that I'm unable to change the VGA cache with this one. Keep getting the error:

MTRR setting failed: -8
MTRRs are not supported.

Same here. I suppose the utility was written for Intel CPUs.

Reply 18 of 19, by DoomGuy II

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5u3 wrote:
DoomGuy II wrote:

Just tried the MTRRLFBE tool. Seems that I'm unable to change the VGA cache with this one. Keep getting the error:

MTRR setting failed: -8
MTRRs are not supported.

Same here. I suppose the utility was written for Intel CPUs.

It's odd, considering what I've read so far is that the AMD K6-2 (stepping 8 and above) and the K6-3 have MTRRs (two to be exact). What's more odd is that WCPUID reported my CPU as a K6-2 stepping 12, yet it says MTRR is not supported, which makes things confusing.

Official Website: https://dg410.duckdns.org/

Reply 19 of 19, by 5u3

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DoomGuy II wrote:
5u3 wrote:
DoomGuy II wrote:

Just tried the MTRRLFBE tool. Seems that I'm unable to change the VGA cache with this one. Keep getting the error:

MTRR setting failed: -8
MTRRs are not supported.

Same here. I suppose the utility was written for Intel CPUs.

It's odd, considering what I've read so far is that the AMD K6-2 (stepping 8 and above) and the K6-3 have MTRRs (two to be exact). What's more odd is that WCPUID reported my CPU as a K6-2 stepping 12, yet it says MTRR is not supported, which makes things confusing.

No, it's not really odd, K6 processors have fewer MTRRs than Intel CPUs and maybe they are set in a different way. Athlons have their MTRRs organized like Intel, on these the MTRRLFBE tool works as expected.

DoomGuy II wrote:

I just found another utility which is MXK6OPT, but I can't seem to get a hold of it. Does anyone by any chance have it?

I've uploaded it to Vogons a few years ago: Here you are. Note that it doesn't allow you to disable write combining, so it won't fix the artifact issue in Terminal Velocity. It is great for playing VESA 2.0 high-res DOS games though.