Do temporary files and unused entries in the Windows Registry slow down a modern Windows computer?
I am sure you have heard the arguments.
Some say that it does not matter how many temporary files you have. They are leftovers. They are not being used by the Windows operating system. Modern SSD drives are fast and if these temporary files have not filled up the drive, they will not affect the performance of a computer. Further, the Windows Registry is just a database. Unused Registry entries are simply ignored and will not affect performance. Even if they do affect performance, it will be minor.
Others say that these temporary files still need to be analyzed by Windows when using a computer and searching for data. Further, the entire Windows Registry must be loaded into memory. And Windows has more to search through to get what it needs.
I have always been in the second camp. Windows just feels slower to me when it is not cleaned up. But I had no way to test this.
I watched two YouTube videos testing this debate and found the results interesting. They were from Macecraft Software, the maker of the jv16 PowerTools.
Video Test 1
In the first video, Macecraft tested whether temporary files and Registry junk can slow down a modern Windows PC. And, if so, is it noticeable to the end user? Their benchmark was a freshly installed, activated copy of Windows, fully updated and with only Firefox installed on the system. They used three metrics:
- Time to desktop – How long does it take for the desktop to load up to the point where the wallpaper is visible on the screen
- Time to idle – How long does it take for the computer to fully load. This was determined by using the Windows Task Manager to see when the overall CPU usage dropped below 5%
- Time to open a website – How long does it take to start the computer, wait for the CPU usage to drop below 5%, and then launch Firefox to completely open a web page
Macecraft loaded junk data onto the same system and ran the benchmarks again. The junk data consisted of 30,000 temporary files of three different types in three different temporary data folders. A total of 270,000 files. To reduce drive usage being an issue, each file was small at about 8 bytes. They also added about 120,000 Registry keys and entries to the Windows Registry. Note, that the junk data was posted on their site, but I will not link to it as I do not want any DCT readers to accidentally download and load it.
|Clean System||With Junk|
|Time to desktop||23 sec||62 sec|
|Time to idle||41 sec||102 sec|
|Time to open the website||57 sec||118 sec|
Wow, that is a big difference – more than twice as slow! The conclusion was that having a lot of temporary files and Registry junk clearly slows down your computer.
Video Test 2
Macecraft received some criticism. First, it was suggested that this benchmark should have been run on a real computer, instead of using a virtual machine. Second, some thought that Windows File Indexing or the Windows Security Antivirus could be affecting the results.
In the second Macecraft video, a new virtual machine was created and File Indexing was disabled. The clean system benchmark was repeated. Then, the junk data was loaded. Windows Defender Antivirus was run with its full scan option. The junk system was then benchmarked. In addition, this entire test was repeated on a physical computer instead of a VM.
|Clean VM||VM with Junk||Clean PC||PC with Junk|
|Time to desktop||20sec||59 sec||28 sec||40 sec|
|Time to idle||35 sec||87 sec||55 sec||74 sec|
|Time to open the website||49 sec||107 sec||68 sec||97 sec|
Although the difference is not as great on the PC as it was on the VM, these tests are consistent with the test in the first video. They show that many temporary files and Registry junk data can slow down a modern Windows computer. Further, the slowdown is not related to Windows File Indexing or Windows Defender.
This was obviously a limited test. Plus, the test was performed with both temporary files and Registry data at the same time. We do not know if it was temporary files, Registry data or a combination of the two that caused the performance impact. However, it does show that having many temporary files and/or junk Registry data can have a major performance impact on a Windows computer.
Personally, for junk cleaning, I have been using the free portable versions of Wise Disk Cleaner (read Jim Hillier’s review) and Wise Registry Cleaner. While I find their interface confusing, Jim Hillier prefers Privazer. Let me know in the comments if you clean your system, what you use, and if you notice any performance differences.