> why didn't he just fit the two H100s into a better desktop box?

I expect because they were no longer in the sort of condition to sell as new machines? They were clearly well used and selling "as seen" is the lowest reputational risk associated with offload

There also weren't H100s available to scavenge. GH200 puts the Grace CPU and H100 GPU on a big module with a custom form factor and connectors, so the only viable route for using those GPUs was to keep all the electronics together and build a suitable case and cooling system around them. There wasn't any way to adapt any of this for use in an ordinary EATX case or with a different CPU, because the GPUs weren't PCIe add-in cards.

At that pricing I honestly thought they fell off a truck. Even well used H100 go for more than that entire system. In the US an RTX A6000 Ada is already close in price.

These are on a custom board from Nvidia, so its not possible to separate them. I think the seller usually gets H100's and them into a custom case, with a PCIE adapter to the server GPUs.

This thing too unwieldy to make into a desktop (you can see how much effort it took), and was in pretty bad condition. I think he just wanted to get rid of it without having to deal with returns. I took a bet on it, and was lucky it paid out.

We build these desktops from Nvidia servers we buy from reputable manufacturers like Pegatron, Gigabyte, Asrock Rack, and many more.

H100 PCI and GH200 are two very different things. The advantages of Grace Hopper are much higher connections speeds, bandwidth and lower power consumption.