I am looking into replacing my home server / NAS, and I considered the atom server chips, but they seem just so expensive for their computing power, and also not very power efficient. The 8 core C2750 has a passmark of 3800[0], with an abysmal single thread performance of 579, and still has a TDP of 20W, and the mobo+cpu assemblies go for ~400$.

For way less, if you're willing to five up on ECC, you can get an i5-7500T and a pretty good motherboard, bringing your TDP to 35W but having a passmark of 7055, and most importantly, a single thread rating of 1924.

This might not matter much if you're use is exclusively NAS, but I will probably end up running some virtualized or containerized server, or streaming video possibly transcoding on the fly, and I'm afraid the Atom might become a bottleneck.

Is there a solution that is somewhat competitive with the i3/5/7 on price and power, and has ECC? And, ideally, that comes in a Mini-ITX form factor?

[0] Obviously the PassMark score is only a ballpark estimate to get an idea of how fast is a chip, but still.