Does reinstalling Windows really boost performance? Let’s bust a PC myth

If you’ve been using Windows for a long time, you’ve probably been told to periodically reinstall the operating system to keep it fresh. I remember I used to reinstall Windows XP every few months back in the day to keep it zippy. But is this necessary in 2025? Will Smith ran the numbers in a deep dive investigation—and they might just shock you.

In short, the answer is no. Based on Will’s personal Windows 11 video editing and gaming desktop, a Ryzen 9800X3D machine with 64GB of RAM, there was almost no difference between a PC that’s heavily customized and running for over a year versus a clean installation. He also tested it on the even more powerful 9950X3D.

The benchmarks showed a difference of about 3 percent for single-core tasks, and maybe a tiny bit worse for multi-threaded applications. In fact, some benchmarks showed an improvement in the “dirty” setup, with an SSD full of Will’s games and personal projects and RAM buzzing with background programs like Dropbox. Adobe Premiere ran 8 percent faster on the older setup. WHAT?

Gaming tests were a little more demonstrable. Cyberpunk 2077‘s built-in benchmark showed a 2.5 percent improvement on the refreshed machine, with an even better improvement for 1 percent lows. But once you turn up the visual settings with path tracing to really tax the graphics card, once again, the “dirty” machine showed a tiny advantage over the fresh install. It’s approaching the margin of error for a lot of these tests. F1 2024 and Rainbow Six Siege showed dramatic improvements on a fresh machine… with frames so high your monitor probably can’t actually display them.

Foundry

So, these results might be shocking if you’re used to the idea that a fresh Windows install is always better for performance.

Adam and Will point out that this isn’t an exhaustive scientific test, though, and Will is a power user who knows how to keep Windows running well. But unless you’re loading up your computer with a million startup programs and dozens of Yahoo Toolbar-style crudware, it seems that a Windows refresh won’t give you the dramatic performance improvements you might have seen 10 or 15 years ago.

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