Many qMRMLThreeDWidgets impact application performance

If my application which base on slicer, need many qMRMLThreeDWidget, may be more than 10 qMRMLThreeDWidget. Is this will degrade the window rendering perfermence? and how do i do? Thanks for your help!

There will certainly be overhead but exactly how much depends on the data and how often you update it. The best thing to do is make a small example script and see how it performs. Use a profiling tool if you can to see where the application is spending time.