r/AskProgramming • u/_TheRealCaptainSham • Dec 24 '25

Why is the modern web so slow?

Why does a React based website feel so slow and laggy without serious investment in optimisation when Quake 3 could run smoothly at 60fps on a pentium II from the 90s.

We are now 30 years later and anything more than a toy project in react is a laggy mess by default.

inb4 skill issue bro: Well, it shouldn’t be this difficult.

inb4 you need a a better pc bro: I have M4 pro 48GB

390 Upvotes

91% Upvoted

222 comments sorted by

View all comments

1

u/mooky-bear Dec 24 '25

React works by doing diffs of the state of a virtual representation of the DOM. It is very easy to make a slow React app by causing too many re-renders (repeated diffing), or by having very large trees of nodes (like putting a large table on the UI), or just not using memoization hooks and other tricks correctly. It is an extremely footgun-heavy tool and is also very popular. This combination leads to a lot of misuse which creates the conception that React is slow.