You can try running nvOC and then adding AMD driver for your 380x... but the automated setting of power and OC is effective on NVidia, but not on AMD right now.

(Under Linux. Under Windows, AMD tweaking works better. It's a function of the drivers available, so no good solution for Linux, right now. I think that's part of why rxOC gets less attention - until drivers make tweaking more possible, there's not as much demand for rxOC.)