I stopped clearing Windows caches after discovering it was silently costing me performance

Published Oct 1, 2026, 8:00 PM EDT Abhinav pivoted from a career in banking to pursue his first love in writing. Even while working full-time, he continued contributing as an editor-at-large, a role he has held for more than 7 years. A lifelong tech enthusiast who has built three gaming and productivity powerhouse PCs since 2018, his passion for technology keeps him closely following the semiconductor industry, from NVIDIA and AMD to ARM. His MSc dissertation explored how artificial intelligence will reshape the future of work, reflecting his curiosity about the wider social impact of emerging technologies. Every once in a while, a Windows 11 optimization guide will tell you to "clear your cache" to reclaim some storage space on your SSD or speed up your PC. It's probably one of the most repeated maintenance tip that gets passed around on tech forums as well. Most of the time, it's generally harmless, but depending on what you clear, you could be gaining just a few hundred megabytes of storage in exchange for long loading times and additionally making Windows and apps redo the work they have already done. As with anything, there's a time and place for clearing caches, and that time is when your drive is running low on space or if something has gone wrong. Treating this method as routine maintenance can often be counterintuitive, though. Here's what the three most popular cleanup options remove, and what you sacrifice to get some space back. The Settings cleanup is harmless, unless you tick two boxes Thumbnail and shader cache aren't junk, whatever the list calls them Perhaps the most popular way to clear cache on Windows 11 that most users will be familiar with is Settings > System > Storage > Temporary files. Through the Settings app, Windows gives you a list of things it considers "safe" to remove, but the problem with this familiar approach is that the list mixes leftovers with caches that your PC routinely requires. Anything related to Delivery Optimization is fine to clear. These are the files that Windows downloads as a part of its update delivery system and stores temporarily so that updates can be shared with other PCs on your local network or the internet. Windows already manages this cache itself, sets a default cache expiration date (which is exactly 3 days) and the default maximum cache size is 20% of disk capacity. The two that I prefer to leave alone are Thumbnails and DirectX Shader Cache. Windows Explorer uses its thumbnail cache to avoid rebuilding image and video previews every time you revisit a folder, while the Windows DirectX shader cache stores graphics work your games have already done. If you empty either, Windows and applications will simply start rebuilding it from scratch, and function slower than usual. That being said, there are some special circumstances that warrant clearing the shader cache and thumbnail cache. For example, Epic Games recommends clearing the Nvidia DXCache (and the equivalent AMD DxCache on AMD systems) when titles like Fortnite deliver below the expected performance or if excessive stuttering is observed on DirectX12. It is worth noting that these are separate from the Windows DirectX Shader Cache entry. You can also keep an eye on the size of the DXCache size through a utility called WizTree, which is how I discovered an Nvidia setting had allowed it to balloon up to 40GB, which is a rather disproportionate amount of storage for a cache whose job is to make games load and run more smoothly. Similarly, a user might want to clear the thumbnail cache for a slightly different reason. Windows can retain thumbnail data even after the original files have been deleted, which can matter if you keep sensitive photos or use a shared PC. Outside these specific use cases though, there isn't much performance or storage to be reclaimed clearing these, and doing so only makes your PC work harder to rebuild them over time. Clearing Prefetch can make your app launches slower It looks disposable, but Windows and your apps have a use for it Windows introduced Prefetch in its Windows XP era, and it continues to persist on modern Windows 11 systems. What it does is basically record which files and resources an application requires during startup so that the OS can preload them more efficiently on every subsequent launch. The common advice is to open C:\Windows\Prefetch and delete everything inside it to boost your system's performance. There's very little to gain from doing this, though. Not only is it redundant (Windows simply recreates the files as you launch those applications again), your frequently launched apps will be measurably slower upon startup, which hits your workflow where it hurts the most. There are legitimate reasons to clear Prefetch, though, but as with the rest of the items I've listed, most of them involve troubleshooting specific Windows problems. As far as storage is concerned, there really isn't much to reclaim considering the size of the Prefetch folder on the average PC. Manually emptying the Temp folder by hand skips a check Windows runs It's not always wise to clear %temp% One of the quickest ways to clear temporary files is to hit Windows + R, type in %temp%, and then select all and delete everything you find. On certain systems, it'll clear the most junk out of any other approach, but it also happens to be the bluntest in what it does. Disk Cleanup (and Storage Sense) both deliberately skip temporary files that have been modified within the last seven days, and they do so because it's a built-in safety rule. Manually selecting and deleting everything in the %temp% folder, as you'd expect, ignores that filter entirely. Microsoft's description of these temporary files says that programs usually clean up after themselves when they close, and anything that's left untouched for more than a week is generally safe to remove. Manual intervention here throws the seven-day rule out of the window. Deletion of some files may be blocked by an in-use error, but that's applied only to the files that are in use at the time when the action is performed. The cost of this error is small, but nonetheless, noticeable. Microsoft's .NET documentation notes that single-file apps that use extraction unpack themselves into a .net folder inside the Temp directory before they run, so clearing it means they have to unpack all over again on the next launch. Not every cache file is junk What most guides on the subject tend to forget (or omit) is the fact that caches exist because a process was slow the first time, and clearing it makes it slow all over again. That being said, there's merit in clearing cache files in certain specific situations, such as when an app is throwing errors, facing performance issues, or if a cache file is bloating beyond its usual size. The key mistake that one should be mindful of is treating every cache file as junk. Likewise, deleting every cache file doesn't yield a measurable performance uplift or free up storage, and can often be counterproductive in practice.