Hello. So I finally managed to find time to upgrade to 5.4.0.x.
Ampitube 5 seems to load faster than before. But I can confirm, I am seeing a similar behavior in CPU as others have mentioned on the thread . I tried it in both stand alone as well as within the DAW. Basically, clicking the double amp and then going back to single seems to bring down the CPU usage by a bit. I am running on Windows 10.x on a slightly older Intel Xeon processor.
But for most part, have not run into issues with the application thus far and I tried some of my projects in the DAW and the settings are still intact, so that's more important for me.