Keeping the AC charger plugged in in parallel with the TB from the docking station seems to have solved the problem. Performance is normal when I game like that. Not the most elegant solution, but it works. My guess is that there is a compatibility issue with the dock.
I am having a problem with my XPS 7590. When I run it plugged into a WD19TB via TB the fan works loudly since startup and the performance throttles to the point of being unable to watch a Youtube video or play games that previously worked with no problems. The problem persists even after I remove it from the docking station and usually fixes itself after some time. I it may have something to do with the power mode.Drivers are up to date, and a fresh install did nothing to solve the issue so I am suspecting hardware or some of the latest BIOS updates. I also have an XPS 9500 and don't experience any of these problems when using it connected to the docking station. Anyone run into a similar problem? It used to work fine until a few months ago.
XPS 7590 - loud fans and poor performance when using WD19TB