system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 Why does it take a computer minutes to search if a certain file exists, but a browser can search through millions of sites in less than a second?
gpt
A browser can't do that. What it *can* do is send a request to an enormous data center which has *already* read through those millions of sites, and has created an index of their contents, So when it gets a request to search for a word, it just has to look that word up in its index, and it can go "yep, that occurs in these websites".

So there are two pieces of trickery involved. One is that all the hard work has been done ahead of time, indexing millions and millions of websites *before* receiving your request.
The other is that your request isn't handled by your computer, but by some of the biggest data centers on the planet. Literally hundreds of computers may be involved in answering your Google search query.