Play From Here in Viewport,
Then turn on the following stats ( ` button to bring up the command prompt):
stat fps (this will bring up the MS per frame)
stat unit (frame times for different parts of the engine)
stat d3d11rhi (this will give more interesting rendering info)
Take a screenshot of all to get an idea of the cost.
(Not that I'm already at this point in my demo game but I'm being taught this at work)