There are some debatable licensing terms in various Nvidia driver releases that prohibit the use of consumer cards being hosted in "datacenters".
But the real issue is physical form factor and power. As has been noted in the press, etc, something like an RTX 3090 (and more so 4090) is literally designed to push frames as fast as possible power and heat be damned. They're multi-slot (which results in poor density), have card design/cooling challenges, power configuration issues, etc.
There's a story out there about the only dual-slot RTX 3090. Gigabyte came up with one (I have several - they're great) but supposedly Nvidia put pressure on them to pull them from the market[0] because people were putting them in x8 server configurations and using them instead of their much more expensive datacenter products.
But the real issue is physical form factor and power. As has been noted in the press, etc, something like an RTX 3090 (and more so 4090) is literally designed to push frames as fast as possible power and heat be damned. They're multi-slot (which results in poor density), have card design/cooling challenges, power configuration issues, etc.
There's a story out there about the only dual-slot RTX 3090. Gigabyte came up with one (I have several - they're great) but supposedly Nvidia put pressure on them to pull them from the market[0] because people were putting them in x8 server configurations and using them instead of their much more expensive datacenter products.
[0] - https://www.tomshardware.com/news/gigabyte-rains-partners-pa...