Please don't post snarky dismissals to Hacker News. It degrades the community.

If you have a substantive criticism to make, please make it neutrally, so those of us who don't know what you know can learn something. Putting others' work down distracts attention from the subject matter, makes you sound like a jerk, and makes HN a bad place to be.

The article may not be news for you, but it doesn't pretend to be a comprehensive guide: it introduces common issues and explains their relation through an experience report. We do need to talk more about garbage collection. Many developers do not understand very well how GC works, and there's a lack of high-quality discussion online. The article and the discussion it's sparking helps demystify the topic.

The point of the article was to show how the % of used memory will affect performance in a non-linear manner. It's obvious once you know, but it's not if you've never experienced it before.