I also got one of these cards in a Dell Dimension XPS B866 I picked up from a retro hardware liquidator guy. Neither of us knew what we were looking at at the time, but I was surprised to see a Geforce 256 with DVI-D and 64MB ram so I figured it was something interesting. This was a top-of-the-line gaming PC of the time, I think. There is a shroud on the CPU heatsink to convert it to blower style and also a green plastic shield around the AGP slot for some strange reason.
The PCB code on the back is 180-P0011-0100-C05. The DDR SDRAM is 8 chips labelled HY5DV651622. There is also a handwritten serial number. I wonder how many of these cards were made? It seems like Dell OEM circa year 2000 is the only source.
I was planning to replace whatever I bought with a Geforce 4 MX460 but I guess I can just keep this.