Why is Unity not using all the power available?

This is probably not Unity-specific, but I can't figure out what's going on. I have Unity 5, 64-bit, running on a solid state drive with eight cores. Why is it only using 13% of my available CPU? I frequently have to reimport files due to other bugs / team unsavviness and this takes hours when it should take minutes - at least, based on the specs I seem to have.

Specifically, new image files were added (lots and lots of them), and Unity's now importing and building libraries and whatever. Disk access should be instantaneous; how do I remove the CPU cap?

Two images; task manager: https://www.dropbox.com/s/l18efrwkr9pdqi5/thirteen.png?dl=0

And CPU inspector thing: https://www.dropbox.com/s/9sgvkmd6zw2ohld/thirteen%202.png?dl=0

Is there anything I can do to make Unity go faster when it's importing? Any plugins that might affect this (we have a ton of plugins in this project)?

I want Unity to use MORE cpu; all the questions I see on the interwebs are trying to get it to use less. :(