Performance on Win 10 vs OS X

I’m trying to move to using Docker to do internal testing for some web dev work, and I’ve noticed that I get significantly worse performance using Win 10 vs OS X on the same machine (we have a mixed dev environment internally, so if I’m to foist this on people it needs to work well on both).

Running our test suite on the same machine with the most recent Docker stable version, using the same linux container, I get a run time of 279.818 seconds under OS X and 1450.188 under Win 10. Basically a factor of 5 drop off.

My first theory was that it might be the CIFS mount on Win 10 was the bottleneck, but if I copied my code onto the container’s disk, I still get terrible performance.

Any pointers on where I might look for issues that could be causing this, or is it just par for the course?