Hi jhoskins. Thnaks for the feedback. I tried this, but it made no difference. My VI loops every 37 msec, and takes about 12-13 msec to read the data (2048 x i32 array). I am already using "Wait until next ms multiple" , with a value of 37 msec, to get the required loop time (which I calculatem based on the sixe of the Dsp's rotary buffer). So, when the VI has done its 12 msec read, plus about 2-3 msec data processing, it should hand control back to the OS and be idle until the 37 msec is timed out. Adding a wait (ms) with 0 as the time value would merely hand control back to the OS, which my VI is doing anyway, so I dont see how this can help. Anyway, the OS stops everything for about 250 msec when the mouse is left clicked on a titlebar and held down - this seems to be much too long. I am still at a loss.
