You're close. Highlight those the nets you don't want to see during a move in the View List, then uncheck the box: "Traces Plus the Following Unroutes". This will disable the selected ratsnests during a move, but you also won't to be able to see any existing routes. So this technique is best used during initial placement before routing, but it can be done later if you want. I always assign colors to these nets, so their connections are easy to visualize without a ratsnest.
It is also easy to forget this has been set up, and when you do start routing, you (and by you, I mean me, I forget all the time) you'll wonder why you can't see the traces and vias you know you just routed and added. So then you go back and check the box you unchecked earlier.
As for the slowing your computer up part, you could instead change the Routing Topology of the biggest nets to "Protected" using the Setup/Design Rules.This will eliminate most of the recalculation time you're experiencing, but it is a workaround in the sense that when you make the ratsnests visible for the large nets, it will be a tangled mess. You'll have to change the topology again if you want them minimized.
Thank u for help!
It works fine for me keeping protected topology for nets who have a large number of connection ( e.g. GND or Power ).
I'm working to a routed PCB and change net visibility for any move action is not a practice idea!!!
At the end, when i finish work, I'll rechange this setting.
Have a nice day!