Would you recommend to use a RPi 5 or a second hand Lenovo mini pc (i3 6100t, 8gb ram) or something else?
Mini PC
Overwhelming majority of my servers are tiny/mini/micros.
Raspberry pi: No. Or, at least, not without doing something to make sure you have a real storage backend and aren’t just running it off an SD card. The wear on SD cards is exaggerated and largely minimized if you use an OS that is configured to be aware of it but you are also increasingly relying on a ticking time bomb.
Mini PC/NUC? I am a huge fan of these and think they are what most people actually need for stuff like home assistant, adguard, etc. Just understand you are going to be storage limited sooner than you expect and you can oversubscribe that CPU and memory a lot faster than you would expect.
My general suggestion? Install proxmox on the mini PC and deploy on top of that. If/when you decide you want something more, migration is usually pretty easy.
And if you just want a NAS? It is really hard to go wrong with a 4 bay NAS from one of the reputable vendors (which may just be ugreen at this point?) as those tend to still come out cheaper than building it yourself and 4 disks means you can either play with fire with RAID5 or not be stupid and do RAID1.
Mini PC. Beelinks with the N100 chip are absolute beasts at doing video encoding at low power.
I also recommend Beelink. I’ve been running an eqr6 (ryzen) for almost a year and it’s been awesome.
Use whatever you have lying around when you start and then when you need new hardware for a certain purpose you can buy it going with the system requirements of that software.
I built a home server based on an Intel N100 motherboard a while ago. I’ve put proxmox on it and run my Home Assistant installation, Nextcloud, several other stuff and even my router as an OpenWRT VM!
I chose to go the N100 motherboard route mainly due to the flexibility it offers. But you can just buy a N100 based NUC and you get effectively the same performance and incredible low power consumption.
I would recommend against the Pi 5. It is way underpowered in my opinion. Plus with a x86 system you just have a lot more software compatibility.
I bought a generic N150 based minipc for a firewall & router (running OPNsense), and repurposed an old desktop PC as a server to host immich, paperless, nextcloud, etc… I considered both RPi and mini pc for the server, but I needed a few TB of storage and wanted redundancy. Spinny disks were a much more affordable option than SSDs, and minipcs and Rpis tend to not have much space for those drives. You can add on storage to them, but then they just become clunkier and more expensive than the old PC I already had laying around. Power consumption is probably a few watts higher on the PC than a Pi would be, but it’s not terrible.
That’s why I went the direction I did. I’m 3 about or 4 months in, and it’s been solid so far.
Whatever is cheapest. When youre first starting out basically any hardware will do, it just needs to boot Linux. As you progress and find more stuff to put on the servers, you’ll discover what you’re real hardware needs are.
When I first started, it was a hand me down single core AMD Sempron machine (socket 754!) that I later upgraded to an Athlon64 and 4gb of DDR. I managed to bodge that poor thing into running a Minecraft 1.5.2 server.
Personally I would stick with the i3 machine since I am assuming it’s an office PC that can be had for cheaper than a Pi 5 (which is quite inflated in price IMO). x86 still retains better software support vs ARM and they are significantly easier to attach large cheap storage to via SATA. Power cost will be greater but I doubt an office i3 pulls more than 70w wall power at full load.
When youre first starting out basically any hardware will do, it just needs to boot Linux.
Unless you already use Linux, you don’t need to start with Linux. Windows works perfectly and is significantly easier for most people as it’s what they already know.
A 35W i7-7700T mini PC from 2017 will absolutely spank a modern N150 in single and multi–threaded applications, and uses very little extra power to do so.
Mini PC is the way to go.

I love my micros.
I’ve have amazing luck with both Beelink and Minisforum computers. They’re relatively cheap and excellent quality.
I personally use the Beelink ME Mini and it’s been able to handle just fine about any server tasks I need it to, not to mention the wildly expandable storage.
Beelink ME Mini
Would something like this be suitable as a NAS + Jellyfin + Home Assistant box?
I just repurposed one of our older PCs for that task. Slap Ubuntu on it, install webmin, and you’re set up.
What is webmin, i’ve never heard of it?
Linux server administration tool, web interface based. Makes managing servers way easier.
I would avoid a Raspi/ARM at all costs. But there is a third alternative: A x86 SBC like a Zima Board or blade might be exactly what you are looking for. Small, powerful enough and far easier than an ARM to maintain.
Raspberry Pi 5 exists?
Oh neat! https://www.raspberrypi.com/products/raspberry-pi-5/




