Much advice has been given on how to keep your computer running smoothly, as well as how to fix it when it has become slow. We have even published a Windows on Speed guide, written by yours truly. One thing that hardly ever makes Windows faster, however, is cleaning the registry.

The often repeated tale, that registry cleaners can improve a computer's performance, is a myth. The unfortunate truth is that registry cleaning can cause serious issues. The potential damange can range from money wasted on a registry cleaner, time wasted on cleaning the registry, an issue caused by 'cleaning' registry files that were actually important, and in the very worst case to a corrupted registry and a computer that will take forever to boot. None of this is worth a theoretical and in the best of cases minimal performance increase.

In a similar article, Chris has elaborated on what the registry is and what registry cleaners do. He has done an excellent job at showing you why registry cleaners by design cannot hold up to what they promise.

I am going to look at the hype around registry cleaners from a slightly different angle. What is it that actually does slow down a Windows computer and how does the registry play into this, if at all?

do registry cleaners work

Let's look at three of the key causes for a slow computer that could theoretically be improved by cleaning or otherwise optimizing the registry.

1. Disk Fragmentation

When your hard drive fills up with data, and when files are edited and deleted, disk fragmentation cannot be avoided. While the NTFS file system does give priority to storing data contiguously, i.e. in one single piece, it sometimes has to make exceptions. For example if you start editing a file that is tightly embedded within other files with no space between them, Windows has no choice but to write whatever you add to the file to another location on your hard drive, i.e. the file gets fragmented.

Fragmentation slows down your computer because Windows has to fetch all the different parts of a file from multiple locations on the hard drive and stick them back together while loading them into RAM. Only when this process is completed, you can see the respective file.

do registry cleaners really work

So does fragmentation affect the registry? Yes, but not really. Even if registry files are fragmented, reading them doesn't cause a significant loss in performance because the registry is loaded into the RAM when Windows boots and can be accessed instantly while Windows is running.

This brings us to the next point...

2. Maxed Out RAM

By far the biggest factor in slowing down the computer is lack of free RAM. What takes up most of the precious RAM space, is running software. When all RAM space is exhausted, Windows removes inactive RAM data and writes them to virtual RAM, i.e. storage space on your hard drive.

Now when this data is needed, it is copied back to the RAM, but only after something else was removed. These operations cause a significant delay.

do registry cleaners really work

So we just established that the registry takes up RAM space. Wouldn't it thus make sense to clean it up and keep it smaller, so it doesn't take up so much RAM? Theoretically, yes. In practice, however, the amount of space you can save by removing a few hundred registry entries is minimal, so it won't make a difference.

You can, however, achieve significant improvements by either upgrading your RAM (if possible) or by closing software you don't need and preventing it from launching along with Windows.

3. Bad Registry Entries

So finally, we have reached the registry itself. Yes, bad registry entries can cause performance issues. However, under normal circumstances this should not happen. Moreover, newer versions of Windows protect the registry from fatal events, such as a crash during a database update, by keeping two levels of log files. During system boot, the registry can be repaired or reinitialized in case serious damage occurred.

General use issues, such as occasionally installing bad software, can of course not be avoided. If you want to do your registry good, remove and don't install crapware, set up a sandbox to test software before installing properly, and if you do have to uninstall, use a tool like Revo Uninstaller to properly remove program files from your computer, including the registry.

So what if you are 100% sure that you have an issue that can be addressed by cleaning the registry? Well, at least use a trusted tool and don't waste any money on it. A PC maintenance tool we highly recommend is CCleaner and it contains a registry cleaner. Although we endorse this tool, we do not recommend to use its registry cleaner on a regular basis. Be sure to use it with care!

do registry cleaners work

Did registry cleaners ever cause you issues or have you seen them improve your computer's performance? We would love to hear about your experience!

Further Reading on How to Make Windows Faster

Image credits: Binary Vortex via Shutterstock, Snail on Keyboard, Snail on RAM via Shutterstock, Snail on RAM via Shutterstock