I have a Lenovo Yoga II Pro with 8 gig ram, 256 SSD, i7 processor and upgraded to Windows 10 yesterday. I have found the performance is terrible and my previously fast computer is now a complete dog. I went into the settings and selected to optimize Windows for performance, but it doesn't help at all. I am not certain, but it looks like the system is hogging all of my network as well, even though I haven't asked it to do anything.
How do I convert back to my prior version of Windows? I think Windows 10 is not ready for primetime and hope other people are smarter and wait for a better release. I should have followed the advice I give my friends - always wait for service pack 1 to come out and fix most of the bugs and problems!!