Hi Ben, You are correct... Running the VI in highlight execution mode will drive up CPU usage and make it more difficult to see how the VI is performing.
Another way to isolate this issue is to "comment out" portions of your code. Do this by surrounding sections of your block diagram in case structures. You can then "comment out" one section at a time by wiring a false constant to the case structure. For each section you "comment out," monitor the CPU Usage. When you find the problem section, "comment out" smaller portions to further isolate the problem. I hope this helps, Sean C. Applications Engineer National Instruments
