February 5, 2017
"The expectation is that the user agent will run tasks from the animation task source at a regular interval matching the display's refresh rate."The evidence: Edge and IE only support 60Hz well. When it comes to other Hz values (both low and high), both Edge and IE both fail. Worst of all, Microsoft clearly knows about the problems, but their lack of any actions (fixes) tells the whole story -- often marking bug reports as "Won't Fix":
UPDATE: Microsoft has finally acknowledged this issue, changing the bug report to 'confirmed'.