The best way to decrease the time for processing is to reduce the processing that you do. If you've got computationaly intense processing, you may have to consider doing it after the program completes, doing it differently, or reducing the sample size. You don't say what exactly that you're doing. Without that information, it's really hard to say. Also, you say it's taking too much time to process 750K samples but at the beginning you say you take 50 samples/sec for 15 seconds. That works out to 750 samples. If you could attach the program (include all subVIs) that would be a great help.
