I’m looking at some old Intel and Pentium CPUs that are in a NUC. Are cores and max clock speed the only things that matter? Would a Pentium be good enough to run Immich? I have a i7-4790, and the NUCs I’m looking at range from a Pentium J5005 to a i3-1115G4. I do run Docker, does that affect anything?
In terms of raw CPU power, you will rarely have issues with anything newer than 10 years old. But some built in video conversion hardware can differ significantly and power consumption is usually also lower for newer CPUs.
I don’t encourage people to buy anything older than ~2016 or Skylake era. Older chips tend to eat enough power that they’re more expensive over time (usually less than a year after purchase) than newer more power efficient parts. Run the math on power consumption with the chip’s TDP for a year as an estimate and you’ll often be surprised by just how expensive chips from <2016 end up being to run. Cpubenchmark.net will do that for you if you use the comparator, just remember to set your average kWh cost.