I've been running Windows 10 pretty successfully on a couple of systems for the last week or so, and while the OS certainly feels fast, I have wondered how the overall speed and performance of applications and games running under this OS compare to previous operating systems. Often, a company bloats the new software as the hardware is faster and it takes less time to optimize code - saving them money. Take a look at the link below as they cover things like boot times, 3D rendering, browser performance, file compression and a lot more. This is a great read to see how they all stack up.
There are going to be future performance benefits of Windows 10 that we can't measure yet, and even once we can, we won't be able to compare the changes with previous operating systems -- DirectX 12 gaming, for example, will only be supported by Windows 10 and later.
Oh if you've upgraded to Windows 10 and you're finding that your computer is rebooting while trying to install an update - continuously, you're not alone. Find out how to fix that over at CNET.
The cause of the problem... is a bad entry in the Registry, which is the viewable and editable database for virtually all key Windows settings. After failing, the initial installation writes a bad entry to the Registry that prevents further attempts to reinstall the update correctly. Forbes suggests a workaround to the problem, which is also documented on the Windows forum thread.