Eric Schmuesser posted something this morning in response to slowdowns and freeze-ups when moving and transforming a large set of objects. He wrote to try turning the Properties pane off.
When I discovered that the Properties pane could be docked and left open I thought this was great. Somehow though it never dawned on me that when a large number of objects are selected the PP is working its magic on all of them, or trying to. When trying to move, scale or transform that large group both my computer would freeze-up and TBC v5 would stop responding. In v4.12 moving 90,000 objects would almost happen instantly. Today I closed the PP and I can now move 90,000 objects in v5 in just a few seconds too. In an email earlier Alan said he had been told the issue is being addressed in the upcoming patch. Perhaps having the PP open all the time is slowing down other functions.