N100's QuickSync has been good enough for me for Plex transcoding FWIW, though maybe your demands are higher than mine in terms of resolution

I think HTPC hardware transcoding is basically the sweet spot use case for the N100. Its less good compared to alternatives for pushing the game emulation performance.

Can it do that while also running 4 drives in a ZFS RAID array? I've been thinking about building such a system but haven't decided on the CPU yet, so I'm afraid of getting something too underpowered.

In `top` you won't notice a difference in cpu utilization for the transcoding work with an intel iGPU (as long as transcoding is being handled by it, of course).

The N100 is definitely powerful enough run a ZFS RAID array. Depending on what all you'd like to run, it might be enough. Check it out with cpubenchmark's compare feature!

I used a Celeron G4900 (also has an iGPU) as a plex server for years, and it's half as powerful as an N100. The celeron is a fairly slow processor, but for plex it was enough since the iGPU did the heavy lifting.

Very interesting, thanks! What about adding a few other server tasks, like automated backups, and running Immich (Google Photos clone)? I'm seeing a lot of conflicting information online, with some people swearing by the N100 as a home server capable of these tasks, and others saying it's just too slow and something like a Celeron 13100 is needed. Since I can't exactly build a system, and then return the motherboard/CPU if it's too slow, I'm a little afraid of under-speccing it. My goal is to have a 3-5 drive system with ZFS, and use it for NAS, Jellyfin (with 4K transcodes, because of subtitles; probably never more than 1 movie at a time though), Immich photos, and backups.

You're definitely limiting your upside with an N100, but it might be enough like I said. It'll work, it's just a matter of how fast it'll be with everything you put on it.

I'd highly recommend joining the serverbuilds dot net discord. They also have a forum with pre-specced NAS build configurations, complete with pricing. People there are very helpful and will give realistic advice.

I think Jellyfin beats Plex on 4k transcoding (tonemapping?) with the iGPU, but fwiw I do not transcode 4k and add subtitles to them just fine. I use an nvidia shield, which direct plays 4k content with the added subtitles. Hearing about transcoding 4k content just to add subtitles is news to me.