The 3 sec update setting may be an illusion. If you open the 'Raw Data/Time & Sales' window, you will find that JPASSOCIAT quotes do not update more frequently than every 30 secs. Setting a value lower than this is perhaps a waste of resources, both yours and NSEs. I find the update interval to be about 30 secs for NIFTY and RELIANCE, and 60 secs for other scripts.
A free (with registration) resource to view QT under streaming quotes is
ADVFN. With UK stocks such as VOD, BARC in the portfolio, it is useful to test QT paintbar code outside NSE hours.