AFAIK there is no point to doing that. All that is doing is degrading the signal quality.

The SLI setup worked for Voodoo 2 cards, not Voodoo 1.
You had each board handling half of the graphics, but the sharing connection was by the feature connector inside the PC (flat cable on top of the boards).
The pass-through cabling on the outside was for using a normal 2D card in conjunction with the 3D only Voodoo 2 cards, otherwise you would have to have two monitors, with one for 2D windows stuff and the other for the 3D Glide games, which is impractical.

Rwolf wrote on 2024-06-10, 00:21:

The SLI setup worked for Voodoo 2 cards, not Voodoo 1.

I think Voodoo1 did support SLI, just that most cards were not designed with that capability. I believe it was one of the early Quantum cards that did SLI which basically a pair of Voodoo1 cards grafted onto a single PCB.

edited to add:

Looked it up and it looks like there were two Quantum Voodoo1 SLI solutions. The first being a pair of Quantum Obsidian Pro cards, and the second (what I was thinking of originally) is the Quantum Obsidian 100SB-4440, which was two Voodoo1 cards in SLI config on a single PCB.

http://www.thedodgegarage.com/3dfx/q3d_obsidian.htm

That extra Voodoo is going unused. SLI works by having data synced between two cards as they both take on a line each. Having VGA chain two of them won't give them that capability.

Don't listen to any denialists, I have 5 voodoos in SLI in a decent mobo and get thousands of bungholio marks, with the order of magnitude increasing per voodoo card installed

😀

Diamond Monster 3D (Voodoo 1) lacks any header for doing SLI.
As others have said, passing it through accomplishes nothing, As the input signal from the first Voodoo will be literally turned off just like it was a VGA card in favor of the last voodoo in the pass through chain when the 3dfx or GL api gets triggered.

Not mention would most likely degrade performance, as you have 2 cards doing the same work and taking up CPU cycles via the PCI buses, slowing down the Bus and the cpu. And that is if the 3dfx API calls are going to both cards.

The only Voodoo 1 that can SLI outside the Obsidian PRO SB50-2400, is Anthony ZX-C64's custom STONED SHAMAN Voodoo Card
https://www.zxc64.com/shamans/0_863_stoned_sh … s_voodoo_1_sli/

progman.exe wrote on 2024-06-10, 16:34:

Don't listen to any denialists, I have 5 voodoos in SLI in a decent mobo and get thousands of bungholio marks, with the order of magnitude increasing per voodoo card installed

😀

Yeah quite right, with the correct driver you push them fps on a logarithmic scale.

I lived a lie

bernardthehermit wrote on 2024-06-11, 21:54:

I lived a lie

Just a misconception, I would say.

Don't worry, we all have some of those.

Thanks for the comforting words. On the bright side: I now know I have a spare Diamond Monster 3D!

bernardthehermit wrote on 2024-06-12, 08:47:

Thanks for the comforting words. On the bright side: I now know I have a spare Diamond Monster 3D!

And spares are never a bad thing.