Do you see something similar?
I loaded "Afternoon Sun Pad" (chosen at random) into Syntronik 2.
On the main GUI page, playing one to three notes, the CPU load was 04-07%,
Switching to the EDIT page, and the CPU load was 24%,
On the EDIT page, playing one to three notes was 27%,
On the main GUI page, moving the window around gave a CPU load of 38%.
And, playing "Big Phase Pad" in Syntronik 2, the CPU loads were 8%, n/a, n/a and 37%.
By contrast, playing it in Syntronik 1, the CPU loads were 2%, n/a, n/a and 7%.