Due to its nature, video demands a lot from your PC. Video processing demands even more, especially when it has to be done in real time. Whenever your PC is not up to the current task, VidBlasterX will automatically display the CPU Usage window. A red line indicates that CPU usage is over 75% which means it is critical. To reduce CPU usage, try one or more of the following suggestions:
1. lower the frame rate
2. lower the video resolution
3. reencode videos before playing them
4. reduce the number of cameras
5. don't use screen capture, or capture only a small part of the screen
6. try using a different way of interfacing cameras (some webcam drivers are extremely slow).
Another obvious solution is to buy a faster PC, note that not only the speed of the CPU is important but also that of the bus, video card and (when recording) that of the hard drive. This topic is also discussed on the VidBlasterX forum.