Are you trying to get a 5-10 us loop delay in a real-time loop? I tried a simple counter-timed loop (see image attachment) at time-critical priority and could not sustain a 10us loop period. The best I could do with nothing else in the loop was 80-85kHz.
I was confused by your second statement, however, and started to think you might be trying to do Simple Event Counting with one of the DAQ-STC counters. If you're trying to take a continuous high-speed period measurement, try one of the Buffered Period Measurement examples. The DAQ-STC counters can easily measure 5-10us delays continuously.