That's the number of divs combined with the CSS transition animation on each cell. If I remove the animation on each cell it runs much better on lower end devic

That's the number of divs combined with the CSS transition animation on each cell. If I remove the animation on each cell it runs much better on lower end devices (looks a lot worse though). In general though older devices can't handle as many cells. I'm sure you can write hyper specific hand tuned code for this example that will run better, but you'll lose all of the flexibility (and you have to load that hand tuned code first too). I could send down purely a string of data and have either an expression swap classes or wrap it in a web component (you can do both in Datastar). But, in short passing json and running your logic on the client adds up. Like anything though test and measure.