In the example ScatterPlotSpeedTest.py, more than half of the computing time is spend on getting symbol property and making pen and brush. In the more standard case, few symbols (probably just one) is going to be used for all the points. The information about the symbols could be computed once and "cached". I'm not really familiar with GraphicsView, but it might also be possible to "prerender" the symbols and "paste" them at the right place.