Reddit page becomes slow to react and even unresponsive if you scroll down enough to load approximately 400 posts. Reddit video player stops responding first (takes seconds to respond), then page begins to render with delay (scrolling, hovering over stuff still responsive though). Firefox Screenshots start to crash if you try to open them and context menu (on page) can take seconds to open. Here's profiler data (with extensions) https://share.firefox.dev/2DXFYnD Reproducable even with clean profile, it just takes more posts to load to see this. (but at 500 posts you can see that video player can react slowly). Other websites with infinite pages (like VK or Twitter) are working well