anon451647, for your information. I had the slowness problem, and solved it with the Windows Insider build 16241. That build is not available now, because they have released a newer one. I would assume the newer one would also fix the bug, but it might have some new problems. anon913665 Nelson, who used to work with Microsoft, thinks Microsoft is likely to release the fix as a public update within the next couple of months.
My report on the Insider build: Microsoft fix for the slowness of Windows 10 Creators Edition