It must be very system and project dependent, what ASIO Guard 2 give you. I have projects where it has huge impact on the ASIO metering. But who knows how that metering is programmed, I would have to fill the project to its limits to measure a difference. What I do notice is I can using ASIO Guard 2, I can have email, word, Dropbox, backup, etc running without Cubase skipping a beat.