I never really figured it out, but I am staring at a voodoo3 and a nvidia card. I understand these were like SLi but I really never found out what this was.
Was it like SLi? Did it make a buffer in the second card? I am interested but I haven't been able to find out what this plug was for.
Only the VooDoo 2 had SLI back then. You're probably seeing the Feature Connector, which was used to connect TV Tuners, capture cards, MPEG decoders, or sometimes HD Audio cards directly to the GPU for faster bandwidth than was available in the ISA/PCI/AGP bus.
"Their speeds often far exceeded the speed of normal ISA or even early PCI buses, e.g. 40 MByte/s for a standard ISA-based SVGA, up to 150 MByte/s for a PCI or VESA-based one, while the standard 16 bit ISA bus ran at ~5.3 MByte/s and the VESA bus at up to 160 MByte/s bandwidth. The Feature connector bandwidths were far beyond the capabilities of e.g. a 386, 486 and barely handled by an early Pentium."
So it was actual SLi.
I looked up what SLi was once and it said it was originally done in 2004. This predates that, obviously. Is SLi just the way it works?
SLI was originally done in 1998 by 3dfx as Scan Line Interleave. It was reintroduced by nVidia in 2004 as Scalable Link Interface.
Anything before, or between those dates is NOT SLI. The VooDoo 2 1000 had SLI, using a 40-pin connector like that of a floppy disc, but it was not used on later VooDoo cards since VSA-100 and VSA-101 chips had the interconnect capabilities baked in. (Hence the name, VooDoo Scalable Architecture)
Huh, I didn't know that! Thanks!
OG SLI.
Like @Fouquin said above in his first post, with Voodoo3 and late 90's Nvidia cards, it's going to be a feature connector, not SLI (not even scan-line). Neither card would have had that feature. Here's my old Diamond Viper v770 Ultra from 1998:
You can see the feature connector on the top left of the card. Your cards are likely using something similar.