system
Given the following post, respond as if you're commenting on Reddit:
human
I remember times when we all eagerly played Flash games, my PC at those times (mid-end) did not start coolers or eat too much RAM for those games and websites. Now any light html5 canvas rendering seems to send my PC to space mission, due to the sound of the coolers. What has changed?

My friends also noticed this.

&#x200B;

Canvas basically runs as it was some kind of Unreal Tournament 3 game or something.

Maybe I'm missing some settings checkboxes in browser or something?

&#x200B;

I generally try to avoid canvas at all times now, because it just makes my notebook and PC lagging and heating, but at those times when Flash was popular I was pleasantly viewing and interacting with games and state-of-the-art websites build upon Flash.
gpt
WebGL happened. You can actually get at the graphics card through a standard web api now, hence games can be a lot more graphics intensive. There's also a lot of game engines for the web now (Unity for example) that makes it easier for developers to make games, especially if it's just Joe Shmoe in his free time. The downside is you get a lot of extra things that the specific game in question may not need, leading to extra computations eating up your computer.

Some combination of those things, along with websites, in general, being more heavyweight now will add to those problems.