Front end work is just messy, solutions that optimize everything at the same time are rare/non-existent. When I've run into hitches, stutters, etc, it was when

Front end work is just messy, solutions that optimize everything at the same time are rare/non-existent. When I've run into hitches, stutters, etc, it was when I was doing too much of the rendering myself in Javascript, micromanaging the HTML and CSS. A little load time is better than any amount of jittering or hitching, which give me a headache very fast. When you make the Javascript do less of the browser's job, work with CSS rather than against it, your code even drifts a little bit toward elegance. The other thing that has caused it, on reflection, is just too many elements (hundred of thousands or millions) particularly in complex SVG visualizations. If this is your issue, the solutions might include summary statistics, fancy graphics algorithms, or just changing the design.