I regret building this $3000 Pi AI cluster

I thought the conclusion should have been obvious: A cluster of Raspberry Pi units is an expensive nerd indulgence for fun, not an actual pathway to high performance compute. I don’t know if anyone building a Pi cluster actually goes into it thinking it’s going to be a cost effective endeavor, do they? Maybe this is just YouTube-style headline writing spilling over to the blog for the clicks.

If your goal is to play with or learn on a cluster of Linux machines, the cost effective way to do it is to buy a desktop consumer CPU, install a hypervisor, and create a lot of VMs. It’s not as satisfying as plugging cables into different Raspberry Pi units and connecting them all together if that’s your thing, but once you’re in the terminal the desktop CPU, RAM, and flexibility of the system will be appreciated.

The cost effective way to do it is in the cloud. Because there's a very good chance you'll learn everything you intended to learn and then get bored with it long before your cloud compute bill reaches the price of a desktop with even fairly modest specs for this purpose.

It heavily depends on the use case. For these AI setups, you're completely correct, because the people who talk about how amazing it is to run a <100B model at home almost never actually end up using it for anything real (mostly because these small models aren't actually very good) and are doing it purely for the novelty.

But if you're someone like me who intends to actively use the hardware for real-world purposes, the cloud often simply can't compete on price. At home, I have a mini PC with a 5600G, 32GB of RAM, and a few TBs of NVME storage. The entire thing cost less than $600 a few years ago, and consumes around 20W of power on average.

Even on the cheapest cloud providers available, an equivalent setup would exceed that price in less than half a year. SSD storage in particular is disproportionately expensive on the cloud. For small VMs that don't need much storage, it does make sense, but as soon as you scale up, cloud prices quickly start ballooning.