Which one is better as a performance? Win7pro or win10

Windows 7 is slower than 8/8.1 and 10 nowadays; it wasn't designed for the modern hardware of today's computers. No UEFI support and no DirectX 12 either (Windows 10 only.)

That being said, user-friendly UI is a big part of what makes me chose an OS; so I'd go with Windows 8.1 for that (with ClassicShell or Start8 ofcourse.)