I've got a really quick question. Does music effect performance? I couldn't find it anywhere that says it does. So can somebody please tell me?
It can on mobile depending on the hardware and what you already have going. It shouldn't take much of a toll on desktop at all.
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Probably not because it's a perfect candidate to offload on to a different CPU core and run in parallel. Maybe on a single core system, or a really badly designed browser/OS which can't parallelise it, but I think all modern systems are fine.