I am having the CPU usage problem with Samplitude too. Not extensive as Kraznet mentioned, but I used 3 different VSTi; a drum track on Superior drummer; one Piano track using Kontakt and 5 (3 to 4 synth and a Bass) on Independence. There are about 20 audio tracks. When I load the project and check the Ram usage, this project uses about 4.5 G, the CPU usage is around 25-30 when it's not playing and goes up to +60% when played, plus LAB and crackly noise. It's kind of discouraging and I don't wanna keep freeze/unfreeze on every single track when there's simply one single note I'd like to add on it!
I hope the very efficient "Samplitude" will be back on Pro X2!!!