That depends. A lot of the power consumption comes from spinning media. Even very old desktop Intel chips have CPU throttling and consume very little while idle. Corporate desktops, even old ones, are usually quite economical.

You don’t need more than an old desktop with a low powered i3/i5 and a free drive bays to build your first NAS. Just install TrueNAS and get going.

I haven’t sunk much time at it, but I’m not aware of any training data focusing on code only. There’s nothing preventing me from running with general purpose data, but I imagine I’d have a snappier response with a smaller, focused dataset, without losing accuracy.

I am curious about trying an application specific AI. Like just for coding, for instance. I assume the memory requirements would be much lower.