Fusion laggy when working in STP files

[Reno_Raines01]

When editing STP files in fusion, fusion is very laggy. When I have design history on, the simplest command takes a while to recompute the timeline everytime, making Fusion near impossible to use. When I turn design history off it is not so laggy, but then several of the command functions are unavailable .

When I design something from the ground up in Fusion there is no Lag. 

Any steps that can be taken to prevent lag when working with STP files?

Thanks.

[jeff_strater]

we need more information.  There is nothing inherent to STP import that is slow, to my knowledge.  It likely relates to the specific STPs that you are working with.  Can you share an example here, as well some examples of specific workflows that are slow on those designs?  Thanks.