Yes, sorry, it can consume quite a lot sometimes. For me, for example, just the interface consumes sometimes 30-50% of one CPU core. To decrease the CPU consumption, you can hide the Document view (Ctrl/Cmd+1) or the Inspector (Ctrl/Cmd+I) when you do not need them. There is an issue with them which causes such consumption. It will be fixed in the next version of SAMSON.
Will wait :) SAMSON has very cute interface, however such cost of one core for that it is not acceptable!