TL;DR: Put an Epyc cpu in a Dell once, and it will never work again in any other vendor's motherboard? Is that right?
It also won't necessarily work in other Dell motherboards, just ones using the same key as the first.
It's strange Dell would blow the fuses by default, though.
This will greatly complicate the future second-hand market, though. Buying used Epyc CPUs off of ebay in 5 years will become very sketchy for example.
Used SGI to not pick a real vendor.
As in for your example there isn't anything stopping you from buying a CPU from anyone, including US retailers, and using it in an SGI EU motherboard. The CPU itself isn't locked when new, this signing key locking isn't baked into the CPU at the factory. It happens when you plop it into the socket & fire it up for the first time.
I can't buy a used cpu from an SGI US customer and put it in an SGI EU motherboard. I can buy a new CPU from anyone though, but then I can only sell it in-region.
Correct, but that's less a region thing and more this just poisons all used CPUs.
As in you don't even know if an SGI US CPU will work in a different SGI US motherboard. There's no particular reason to assume all SGI US motherboard models will have the same signing key. Within the same model that'd almost certainly be the case, but if it's a different model, especially different chipset, I don't know why they would necessarily strive to keep the key the same across different firmware branches.
> I can buy a new CPU from anyone though, but then I can only sell it in-region.
Er, why? Nothing about this stops you from re-selling CPUs however you want. Or are you still talking about the used market here?