CPU red at 4 % and glitching sound

hello hello these days I downloaded the trial version of AudioMulch. a nice program that I'm going to buy. But I'm having problems. I use AM on win 7 and a focusrite 2i2. I'm noticing that when I start to use the livelooper and the reverbe the sounds come glitch and the  cpu turns red already at 4 or 3%. I set the buffer to the minimum allowed by the program. depends on what? something wrong? I noticed that if imposed as a sound card, basic pc does not give me this problem. what can I do?  thanks to the availability and hope to resolve this issue because I am very interested the program.