AMD's MI325 is slower (maybe 2x slower) than Nvidia B100. Sure it's cheaper and maybe consumes less power but you need more racks, more networking, and more labor to get the same performance.
From Nvidia and AMD, I read sparse fp8 at 7 PFLOPs for B100 [0] vs 5.22 PFLOPs for mi325x [1]
Nvidia doesn't give the dense fp8 so that's the easiest comparison I could get.
[0] https://resources.nvidia.com/en-us-blackwell-architecture [1] https://www.amd.com/en/products/accelerators/instinct/mi300/...
Nvidia drops precision and adjusts via software to sell a new gen.