Now that the cluster is up and running, I can finally calculate the cost of the cluster.

Looking at the hardware first:

Component	Quantity	Price
Radxa X4 N100 4GB	1	68.39€ (as of writing; i paid 52.42)
Radxa X4 N100 8GB	3	91.99€ (as of writing; i paid 70.50€)
Noctua NF-A4X20 PWM	4	15.90€
Radxa 30W Power Supply	4	18.97€
Heatsinks	4	3.00€
Raspberry Pi 256GB SSD	4	34.20€
Total	currently ~ 725.63€ | i paid 552.2€

This is without the cost of the printed case, the brackets, screws, and silicone thermal pads. The cluster specs with this configuration are 16 cores, 28GB RAM, and 1TB SSD storage. Overall I think the price is pretty okay.

Looking at prebuilt comparable systems, like the GMKtec NucBox G3 with 8GB RAM and 256GB SSD, which costs around 128.99€ at the time of writing, it would cost around 516.00€ for 4 of them. This would also include the PSU and case and does not require all this DIY work. The only hardware difference as far as I can tell is the RAM is DDR4 instead of LPDDR5, but without benchmarks I can’t say for sure how much this matters.

This means, that it is definitely cheaper to buy a prebuilt system, but the Radxa X4 N100 is a lot more fun to work with and has a lot more potential for future projects. Also looking at the components, they can all be reused in other projects, which makes this more relevant for me.

I would probably not recommend to buy the boards without a sale, since they so close to prebuilt prices. Sure, some of the components like the SSD and the Fan are of a higher quality, than what you would find in a GMKtec system, but unless you are actually using it for labbing, this is not really relevant.

Power consumption

I currently have only three nodes running, since I am missing some jumper wires to connect the last one. But here is the three node power consumption:

The measurements were taken with a no name smart plug and might not be accurate.

With a 2.5GB switch, 1x 4GB node, 2x 8GB nodes the power consumption with Talos OS installed and idling (really idling, no services) i around 33W.

Without the 2.5GB switch it is around 24W. With kube-prom, metrics server, harbor and homepage.io installed and running it is around 37W.

This is a lot lower than I expected, but I am not complaining. The performance from some quick tests also seems to be great.

Conclusion

Overall the experience was nice. The boards seem great and the performance is great. The only downside is the price, which is a bit high for what you get, especially if you would buy them without a sale. I learned a lot about 3D printing tolerances and FreeCAD, which was great. Also having a lower power home lab is great. I am looking forward to using the cluster for some projects in the future.

A bit off-topic but this project really made me think about the raspberry pi ecosystem. I think the Raspberry Pi 5 is a great board, but the price is a high for what you get. I like ARM and use it in a few production systems, which makes it even more sad, that the Raspberry Pi pricing is the way it is.

Next up: Part 8