Hi @matthewjohnjamieson, can you let us know which version of p5.js you’re using? (this should be in a comment at the top of your p5.js or p5.min.js file)
If you’re not doing this already, you might get a performance boost by using p5.min.js which will turn off some of the parameter validation for the friendly error system.
If that’s not applicable, can you run the performance profiling tools in Chrome or Firefox and let us know where the slowdown seems to be? (here’s a nice tutorial on the Chrome tools in case you need it—please disregard otherwise) 