Boat speed and locating fish

Guys, I cant say enough about how much the Humminbird Mega Side Imaging has changed the game for me. As a tool for finding new fishing spots, I can troll until the batteries die on the terrova, but if I'm not seeing fish on that Helix 9, I'm not getting bit.
Which tells me if I'm looking for new spots, I need to be looking and running the big motor more frequently. So, looking for some input from guys doing this. How fast a speed is this effective? If I'm running 5mph and chart speed matches, can I expect the detailed images of suspended fish I see at 1mph? Any input is beneficial. Thanks

I generally get the best images from running about 3 to 4 mph and running the chart speed on 5 or 6.

:hesaid I normally run chart speed at 5 and Boat speed about 3.7mph. What works best for me :twocents