[thraway123412]

Well, he also needed to add a cooler and a bunch of tubes & eight mounts to get coolant running on each Pi, eight ethernet cables, eight power cables, a power supply with enough outputs, a 16-port ethernet switch, and (correct me if I'm wrong) eight SD cards, if only to store a bootloader that can do pxe.

So eight Pies alone do not make a complete cluster, just as one Ryzen alone does not make a complete computer. A few times eight times cheap can turn out to be quite expensive, depending on how much cheap actually is.

I haven't paid much attention to component prices recently but my rule of thumb for budget builds is to start with $80 for each component that isn't a GPU or CPU. Go with stock cooler, grab 80 for PSU, 80 for mobo, 80 for RAM, 80 for storage, see where you end up. In the same ballpark, but the real computer will pack a whole lot more punch (even if you had less RAM total).

[jamesbfb]

Jeff Geerling did a blog post[0] and video (series) on this very thing a while ago that goes into some of the hardware and costs. Whilst the costs can be negligible, it looks like a hella lot of fun!

[0] https://www.jeffgeerling.com/blog/2020/raspberry-pi-cluster-...

[mbreese]

Don’t forget this quote from that page:

> It's slightly more cost-effective and usually more power-efficient to build or buy a small NUC ("Next Unit of Computing") machine that has more raw CPU performance, more RAM, a fast SSD, and more expansion capabilities.

But is building some VMs to simulate a cluster on an NUC fun?

I would say, "No." Well, not as much as building a cluster of Raspberry Pis!

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You don’t build a RPi cluster for speed or cost or efficiency. You do it because it’s fun. And that’s okay.