Probably a bios issue causing it. The Aopen was never retail in my area but the Giga was so that makes me think bios compatibility. Probably wrong but my 2 cents worth....

I’ll try playing with this BIOS settings and see what happens. I’ll also change the AGP card and maybe the PSU as well. Although if it’s working under Windows then changing those components shouldn’t make a difference.

Looks like someone else here had a very similar issue 3Dfx Voodoo 2 SLI Black screen

Maybe changing the Fast PCI reads would help Re: Voodoo 2 SLI Black Screen

Update on everything I’ve done so far;

- Removed all ISA cards
- Bypassed config.sys and autoexec.bat
- Tried all PCI slots
- Changed AGP card
- Changed PSU
- Changed monitors
- Tried every single BIOS option
- Reverted to previous BIOS version
- Set SSTV2_FASTPCIRD to 0

For a sanity check I installed the Voodoo 2's and DOS SDcard back in the GA-5AA and Tomb Raider and Descent 2 are working perfectly.

Both Voodoo 2’s work perfectly solo in the AOpen AX59 Pro in DOS but as soon as they are installed at the same time I just get a black screen in 3dfx games. SLI in Windows 98 is working perfectly.

I wonder if it’s something like the PCI registers need to be changed? Re: Voodoo 2 difficulties.

If anyone has any other ideas, I'm all ears

Try a slower cpu? When I had problems with TR1 and Descent 2 running a voodoo sli dropping from a 800 P3 down to a 350 P2 fixed it.

buckeye wrote on 2025-02-24, 18:02:

Try a slower cpu? When I had problems with TR1 and Descent 2 running a voodoo sli dropping from a 800 P3 down to a 350 P2 fixed it.

I ran setmul to slow it right down but no luck. The games run fine in SLI with the exact same CPU in the GA-5AA. Thanks for the suggestion though. I’ve spent too much time on this issue. Might be time to give up 🤣

Spent a couple more hours but still no luck. I’ve set SSTV2_INITDEBUG=1 and SSTV2_INITDEBUG_FILE=C:\debug.txt before running the games but the debug.txt file never gets generated.

I’m starting to think the AOpen AX59 Pro is incompatible with using two Voodoo 2’s in DOS. Maybe something specific to Rev 3.1?

zuldan wrote on 2025-02-26, 11:52:

Spent a couple more hours but still no luck. I’ve set SSTV2_INITDEBUG=1 and SSTV2_INITDEBUG_FILE=C:\debug.txt before running the games but the debug.txt file never gets generated.

I’m starting to think the AOpen AX59 Pro is incompatible with using two Voodoo 2’s in DOS. Maybe something specific to Rev 3.1?

That's not it. I've used a couple of CT6670 (12MB V2) cards in SLI together with geforce 2 mx and a K6-III 400 in my AX59 pro and had no issues getting 3dfx games to run in dos, with one or 2 cards - once I patched the games to work on a voodoo2 that is.

Have you tried connecting the video cables to the other card?

Socket3 wrote on 2025-02-26, 18:54:

zuldan wrote on 2025-02-26, 11:52:

Spent a couple more hours but still no luck. I’ve set SSTV2_INITDEBUG=1 and SSTV2_INITDEBUG_FILE=C:\debug.txt before running the games but the debug.txt file never gets generated.

I’m starting to think the AOpen AX59 Pro is incompatible with using two Voodoo 2’s in DOS. Maybe something specific to Rev 3.1?

That's not it. I've used a couple of CT6670 (12MB V2) cards in SLI together with geforce 2 mx and a K6-III 400 in my AX59 pro and had no issues getting 3dfx games to run in dos, with one or 2 cards - once I patched the games to work on a voodoo2 that is.

May I ask what revision your AX59 Pro is?

maxtherabbit wrote on 2025-02-26, 19:19:

Have you tried connecting the video cables to the other card?

Yep

The issue has been resolved! A MASSIVE thank you to the Voodoo guru sdr. He was very generous in answering my personal call out for help. I'm a bit embarrassed as I should have thought to try playing with the cables. The solution was to connect the VGA card furthest away. I've always connected the VGA card to the closest Voodoo card. I guess you learn something new everyday.

zuldan wrote on 2025-02-28, 23:02:

The issue has been resolved! A MASSIVE thank you to the Voodoo guru sdr. He was very generous in answering my personal call out for help. I'm a bit embarrassed as I should have thought to try playing with the cables. The solution was to connect the VGA card furthest away. I've always connected the VGA card to the closest Voodoo card. I guess you learn something new everyday.

The attachment Voodoo 2 SLI Setup.png is no longer available

The attachment TR.JPG is no longer available

This is literally what I suggested two posts ago 🤣

maxtherabbit wrote on 2025-03-01, 01:24:

This is literally what I suggested two posts ago 🤣

You are 100% correct. I didn’t see your post. I read the PM from sdr, got so excited then responded to this thread. Sorry about that. Thank you maxtherabbit!

What I find strange is that DOS only accepts one type of cable configuration and Windows accepts both types. I’ve never heard of this before.

zuldan wrote on 2025-03-01, 01:33:

maxtherabbit wrote on 2025-03-01, 01:24:

This is literally what I suggested two posts ago 🤣

You are 100% correct. I didn’t see your post. I read the PM from sdr, got so excited then responded to this thread. Sorry about that. Thank you maxtherabbit!

What I find strange is that DOS only accepts one type of cable configuration and Windows accepts both types. I’ve never heard of this before.

The underlying cause is that when SLI is supported by the drivers (your windows case) the two cards use a presence detection circuit to determine which one is connected to the video cabling and make that one the primary. When you use environment vars to make stubborn DOS games work (which typically include the one which disables SLI) the primary card then becomes which ever one is enumerated first.

zuldan wrote on 2025-02-26, 19:56:

Socket3 wrote on 2025-02-26, 18:54:

zuldan wrote on 2025-02-26, 11:52:

Spent a couple more hours but still no luck. I’ve set SSTV2_INITDEBUG=1 and SSTV2_INITDEBUG_FILE=C:\debug.txt before running the games but the debug.txt file never gets generated.

I’m starting to think the AOpen AX59 Pro is incompatible with using two Voodoo 2’s in DOS. Maybe something specific to Rev 3.1?

That's not it. I've used a couple of CT6670 (12MB V2) cards in SLI together with geforce 2 mx and a K6-III 400 in my AX59 pro and had no issues getting 3dfx games to run in dos, with one or 2 cards - once I patched the games to work on a voodoo2 that is.

May I ask what revision your AX59 Pro is?

....as far as I know there is only one revision of the AX59 Pro... I might be wrong... I have two boards, they are both identical, and looking around I can't find a "1.0" or "rev x.x" anywhere on either of my two boards.

Glad to see you got it working.