Are the problems with speed using manifold 8 with windows 11

There is nothing about Windows 11 that would change the advice in the Performance Tips topic in the User Manual for Release 8.

All other things being equal, I'd expect Windows 11 to be slightly faster than other Windows editions, assuming, of course, that you have enough memory in your computer to host both the operating system and the application with the project without thrashing.

OK and Thank You for your help Dimitri.

Regards Jeff