I have recently begun using Sonar X1 Producer on my PC laptop (Windows 7, 64 bit) and am now exploring Guitar Rig 4, which is great, except that I'm getting a lot of snap, crackle, pop out of my monitors. The audio interface in use is a Steinberg CI1 USB unit. The input levels on my guitar track in Sonar are under control (not red-lining) and ditto for the levels displayed in Guitar Rig. Any suggestions?
Guitar Rig takes a lot of CPU power when using it in real-time. One thing you can try is setting a different Driver Mode for your audio interface in SONAR. ASIO is preferred, but if you're already using that, you may want to try WDM.