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That is pretty normal, does the same thing in Unigraphics for me.
Look in the graphics settings for an option that tries to force a minimum frame rate and turn it off.
What is happening is that your computer is not powerful enough to keep the frame rate fluid when repositioning your ASM.
In order to allow you to better move the ASM around, it is not rendering every little detail and instead renders a much simpler representation of the parts.
I would personally recommend leaving this setting where it is.
If your ASM is really this large, it can take several seconds to render each little bit of movement when panning, rotating or zooming.
It can make it fairly difficult and more time intensive to reposition stuff.
As with the above, please do not post everything in caps.
Also, double posts are not necessary.
All they do is cause posters to ignore you.