Well, I disagree. I have in my secondary screen GPU, CPU, VRAM and RAM use (through AIDA64), and when I play CMBN one of my cores is at 100% and my GPU (one of them) is at 25-30% maximum.
Moreover, I have tested at different resolutions: from the lowest to 2560*1600 (30" LG). I have tested with the highest possible AA filter through NV CP. I have tested in game enabling or not shadows... And the result is that my FPS don't change and GPU load either. It's not a GPU related problem. It's CPU. I don't have any problem with antivirus nor in whatever other game either.
You cannot check CPU load (your pic) alt-tabbing from the game, because when you do that, CPU load disappears (I have tested 2 min ago). You need a secondary screen or keyboard with screen (G15 or G19 with pluggins, for example) to check the load in game. If you return to desktop to measure it, you don't get the figure, you get 0% of use.
Mate, on my opinion and with due respect, you are wrong.