Scaleway DC5 is large by French standards, rather small by US hyperscaler standards. But the main reason is DC5 does not use classic cooling, thus does not have huge dry coolers outside, which definitely helps for noise (it's adiabatic cooling).

Another fact is just the sheer power density of those problematic north virginia datacenters. I'd bet us-east-1 is not an issue (old building and lower power density), but the newer AI ones are. Just take a look at how much AI clusters eat: a single DGX H200 box with 8 GPUs is 10kW. Most facilities provide 10kW for a whole rack, not 8Us. You're looking at 60kW racks, which is a mental power density: a single aisle trivially gets over the MW threshold. You used to feed rooms with megawatts. Heck, DC5 has 24MW of power, that's only 20000 H200 (again, think hyperscaler scale).

Still about cooling, the load profile is even different. DC5 is a general purpose datacenter, where the load is not full blast. Your AI datacenter has the GPU clusters full blast all the time. That's a LOT of power.

I happen to know pretty well the Scaleway infra and visited others of their datacenters. You can stand centimeters from the noise-dampening wall surrounding the dry coolers and not hear a thing; while almost needing noise protection within the wall.