[Just1689]

I had a cluster of ODroid C2s. It was nice - quad core, 2GB memory. But honestly, only for some workloads.

In my experience memory is a much bigger bottleneck than CPU, net IO or disk iops.

At the moment my favorite home lab cluster is a bunch of old laptops. They're quad cores too but I've dropped 16 GB of memory in each. It's doing a lot better. Right now the cluster is using 21GB of memory.

I'm able to run everything I've wanted as well as the occasional experiment to try something out.

If I could leave you with something - get more memory than you think you will need. That's been my experience anyway.