Reddit recently underwent another new, unpopular redesign, meaning that there are now three different UIs for accessing the website. Out of habit I would look at new-new reddit before remembering to switch to old-new reddit, and quickly noticed that looking at new-new reddit causes my laptop’s fans instantly start spinning.

Here’s a firefox performance profile for 20-30s of each iteration of the reddit homepage. I simply loaded the page and did absolutely nothing.

old.reddit.com: constant ~5% CPU usage with occasional spikes up to ~90%

new.reddit.com: usually 0% CPU usage with occasional bursts up to ~50%

reddit.com (new-new reddit): constant 30% CPU usage with occasional spikes even higher

I don’t have the time or knowledge required to dig into the performance profiler but I would be fascinated to know how old-new reddit ended up more efficient than old-old reddit, and exactly what new-new reddit is doing with 30% of my CPU??