Despite (or perhaps because of) all the bells and whistles, Windows 10 can sometime run a little slower than other systems, particularly on older machines. If you’re one of the new Windows 10 users who feels that they’ve had to sacrifice speed to get the latest version of Windows, here’s how to speed it up.

Make starting up Windows 10 quicker
By default, Windows 10 will ask for the user’s password every time the computer boots up. Although this is an example of security best practice, you may feel it’s a touch unnecessary, particularly if your machine sits in a secure home office.
If you want to get rid of this safety precaution, click on the Search field next to the start menu and type ‘netplwiz’ and then press Enter. Untick the box next to ‘Users must enter a username and password to use this computer’, click apply and enter your password to finish up.
Be warned, however – this will disable all forms of login authentication, meaning that anyone will be free to use your PC. We would discourage anyone who handles sensitive or valuable information from doing this, and password requirements should never be disabled on laptops.
Make shutting down Windows 10 faster
If you like to shut down your computer after a hard day’s work, then you will realise that the process still requires three clicks. To speed this up you can use a shortcut. Simply right-click anywhere on a free part of the desktop then click New > Shortcut. In the Location field, type in the following. 
%windir%System32shutdown.exe /s /t 0
Click on the Next to finish. Now each time you click on that shortcut, your PC will immediately shut down. Be careful though! 
Disable Startup programs in Windows 10
Virtually every version of Windows allows you to disable startup items, and Windows 10 is no exception. Stopping some programs from starting up will speed up the OS. 
To find this option, right-click the taskbar and choose Task Manager, and then click on the Startup tab. Here you can disable the programs you don’t want to start up. 
Remove bloatware in Windows 10
No one likes bloatware (except PC manufacturers) but it does mean your system is slightly cheaper as a result. But you can ditch this crapware. For the most part, these are programs such as disc burning software, backup tools from the manufacturer or other utilities that you don’t necessarily need. 
Why programs such as PC Decrapifier and CCleaner do a sterling job of getting rid of bloatware, if you have a brand new (but bloatware laden) computer, then a clean install of Windows 10 could be the best way of clearing out unnecessary software clogging up your system. 
Make the Windows 10 Start menu and other Windows zippier
The brand new Windows 10 Start menu can be slower to pop up on older machines. This is because making this appear in a whiz-bang fashion consumes compute power. To turn off this animated feature, bring up Systems Properties (type in the search field sysdm.cpl and press Enter.)
Click on the Advance tab, then click on the Settings button in Performance. Untick the box for Animate windows when minimizing and maximizing, then click Apply.
This should speed up not only the Start menu but also all other windows that appear on your desktop. 
If you really wanted to, you can disable all visual effects to really speed Windows 10 up. Just click on the radio button next to Adjust for best performance.
Turn on Windows 10 Fast Startup
With Windows 10 there is a new “hybrid” startup mode that should cut down on bootup times. IT does this by putting the PC into hibernation instead of fully shutting down.
To enable this, click on the Start button and type in “Control Panel” and press enter. In the control panel click on Hardware and Sound. A new page should appear, here click on Change what the power buttons do. Then click on Change settings that are currently unavailable. Finally, tick the box marked Turn on fast startup. 
Disable services on Windows 10
As with all versions of Windows, working in the background are services. While some of them are vital to the smooth running, quite a few aren’t for day-to-day use. If you disable these services, you can speed up Windows 10.
To turn off services in windows, type: “services.msc” into the search field. Then double click on the services you want to stop or disable. 
There are many services that can be turned off but which ones depend on what you use Windows 10 for and whether or not you work in an office or from home. A great guide to the services that can be switch off can be found here
Remember, though, stopping or disabling services can have unforeseen consequences. Many components or applications may stop working properly, so proceed with caution.
Clean up your Windows 10 disk
Windows 10 has a built-in Disk Cleanup tool that is very good at getting rid of unnecessary files. To run its click on the Start button, then click the File Explorer link. Right-click Local Disk C: and select Properties. Where the General tab is, click the Disk Cleanup button.  Click “unnecessary files (temporary internet files, etc.),” then click OK. 
There is also a “Clean up system files” button for advanced users that gets rid of even more files. After this, you can then….. 
Defragment the hard drive on Windows 10
Defragging the hard drive is really only applicable if your machine has a traditional hard disk (it is not recommended for solid state disks). 
To defrag your hard drive, click on the Start button, then click the File Explorer link. Right-click Local Disk C: and select Properties.  Click the Tools tab, then click “Optimize and Defragment Drive”.
Source: http://www.itpro.co.uk/operating-systems/26138/how-to-speed-up-windows-10-2