That's what I assumed, and it was only when I was idly googling for 3dfx stuff a few years ago that I realised it probably wasn't. The 5500s all look to have 2 chips, and are normal sized. Mine had four chips, and it was... large. Like, very large. Also had a plastic handle.

Looked a bit like this one: https://robertkrau.se/blog/3dfx-voodoo-5-6000-stripe-artifac...

Here's one with a Molex connector: http://www.x86-secret.com/articles/divers/v5-6000/v56kgb-6.h... (I can't remember whether it was wires or soldered in on mine, this was 20 years ago and I didn't spend much time playing with it)

I got it from the storeroom at the video games company I was working for at the time. They were having a clear out, and we could take whatever we wanted. This was one of the things I wanted.

(Sadly they didn't let me have the Jaguar devkit, doubly annoying when I later discovered that Atari had put all their Jaguar stuff into the public domain. Mind you, I'd only have thrown that out too as well, probably, so same result in the end.)

Interesting stuff. I worked at 3dfx in the last few months of their existence. All the 6000 I saw had the external psu. I was just an IT nerd so I wasn't involved with the cards.