It's a great concept but I think it would cross the line from 'very slow' to 'so slow it's unusable' at this size. Even if we say you have an NVME SSD that does 7GB/s reads, that's dramatically slower than being able to hold the whole thing in DRAM. Like the difference between 1.3 tok/s in RAM vs 0.1 tok/s with a colibri-like method.
edit: the results I have seen from people trying colibri with fast consumer grade PCI-E 4.0 NVME SSD are 0.1 tok/s on models that are <700B in size, things that are well under 800GB on disk. With something that's 3T in size it'll probably be a lot slower than hat.
For single stream inference of a MoE model, the size of active sparse parameters will matter a lot more than total parameters. This is generally around half of the reported active parameter count - the other half being a dense subset that can be easily cached in VRAM even on fairly modest consumer setups. So the achievable performance may be quite a bit better than a naïve assessment might suggest.
1536GB of DDR4 ECC server RAM is somewhere between $4000-6000 USD used right now, by the time you put in parallel enough NVME SSD to approach good speeds, you'd be approaching that (and also likely running out of PCI-E bus lanes directly attached to the same motherboard to reasonably do so).
Won't the answer (even for a pretty basic message like "hi") at SSD speeds take like a _entire week_ to _start showing useful output?_ (attempting to do 22k average claude code system prompt + 32k thinking tokens thru 0.1t/s throughput)
edit: the results I have seen from people trying colibri with fast consumer grade PCI-E 4.0 NVME SSD are 0.1 tok/s on models that are <700B in size, things that are well under 800GB on disk. With something that's 3T in size it'll probably be a lot slower than hat.