The large number of files that are moved, deleted, and written when upgrading an old version of Windows to a new version means that fragmentation is inevitable. Files become divided into small parts that are scattered across the disk drive and this makes them slower to access.
Windows 10 might seem fast, but maybe it could go even faster by optimising the disk contents.
For a while now, Windows has hidden the disk defragmenter and made it automatically run behind the scenes. It does a reasonable job of keeping the disk drive optimised, but that does not mean it is perfect and cannot be improved upon.
Open an Explorer window, select This PC on the left to show the disks attached to the computer. Right click the C: drive and select Properties on the menu that is displayed.
When the Properties window opens, select the Tools tab and click the Optimise button. As it says, optimising your computer’s drives cab help it to run more efficiently.
When the Optimise Drives window opens, select the C: drive and click Analyse. This shows the percentage of fragmentation.
There is an Optimise button to run the disk defragmenter right now, but click the Change settings button instead. It is set to run weekly by default, but if you use your computer a lot, you might want to run it daily.
It will run more often, but it will have less work to do. It runs in the background when the computer is idle and you will not notice it. However, the disk will be more optimised than a weekly setting.
The Optimise Drives window shows the percentage of fragmentation, but what does that mean? It says the disk is 2% fragmented, but how many files is that, and which ones? Piriform Defraggler can show you. (Get the Defraggler portable version.)
Run Defraggler and click the Analyse button. Afterwards, select the File list tab and click the Fragments column header twice to sort the files with the most fragmented at the top.
Defraggler can be used to defragment the disk instead of letting Windows do it. However, it will not defragment files that are in use and right at the top of the list in the screenshot is pagefile.sys with 136 fragments. This is always in use and attempting to defragment it will get you nowhere.
IObit Smart Defrag is another free tool that is worth keeping on the disk drive. (Get the portable version.) This not only defragments files, but it also has a Boot Time Defrag.
This runs a defragmenter utility just after the PC is switched on and before Windows loads. Turn on all the tick box options and click Configure.
Select the Only next boot option, click Apply and then OK. Reboot the computer to defrag the system files that are in use.
Windows disk defragmentation is OK, but I always keep Defraggler and Smart Defrag around because they provide more options and you can run them at any time to optimise the disk.