I was having stability problems and a memory issue that started very abruptly while surfing . The yoga 3 pro (about 2 years old) would subsequently not complete it's boot sequence. Tried reloading Windows with same behavior.
I ran a diagnostic that would sometimes log a memory fault, but not consistently. I decided that my motherboard(mb) was gone also; but when I opened the back to check the mb part number I decided to lift the fan and heat pipe.
The heat pipe sits on top of the memory, you have to loosen/ remove all 5 screws on the fan-heat pipe assembly and carefully pivot rotate the fan so as not to damage the cable from the fan to the board near the edge of the motherboard. The 3 screws on the heat pipe will stay in the mounting bracket, the 2 fan screws can be removed.
After I pivoted the fan-heat pipe I found that the gray conductive paste under the heat pipe was was all squeezed out from the memory surface (there are 2 IC's, one square and one rectangular). There was a lot of paste on the heat pipe and the PCB board where these 2 IC's are mounted but very little left where the heat pipe lies on the surface of the IC's. The memory was not being cooled adequately.
I cleaned both the heat pipe surface and the memory module using cotton swabs and isopropal alcohol (70% rubbing alcohol from the drugstore), it takes a few minutes and some light friction to get the old paste off both surfaces. Let the area dry thoroughly.
I then reapplied some silver conductive heatsink paste (you can probably get this at best buy or similar store selling computer supplies ( https://www.googleadservices.com/pagead/aclk?sa=L&ai=DChcSEwi6rfbMk5LaAhVGgn4KHdY5Bj8YABAaGgJwYw&ohost=www.google.com&cid=CAESEeD2O4i3Z1yHYAKhLUxhkSj5&sig=AOD64_3N7a_lL2BwqQAtNfOJVAc6bTK9hg&ctype=5&q=&ved=0ahUKEwiJlu_Mk5LaAhUN8WMKHTLWBYUQ9aACCD4&adurl=).
Use this paste sparingly, you will only need one dot on the square IC and 2 dots on the rectangle. Then rotate the fan-heat pipe assembly back to the installed position and tighten the screws on the heat pipe and refasten the 2 fan screws. Take care not to smear the paste while doing this; tightening the screws will squeeze the paste between the heat pipe and IC's to get good coverage to allow the paste to conduct the heat to the heat-pipe.
I suspect that during the original assembly too much paste was used, or even that the paste was allowed to dry out (or both, there was paste all over mine). It worked ok for a couple years but through moving the laptop around the heat pipe lost its contact with the paste and memory chips and the memory was getting to hot to work properly. I think also that silver conductive paste used on CPU heatsinks is better than the stuff used for the original assembly.
My Yoga 3 Pro is now running stably with faster performance and somewhat better battery life. If your problem is similar it is a pretty inexpensive and quick action you can do without having to take the computer to a service person. You will need a very small torx and philips screw driver to remove the screws. Check out YouTube videos for mb replacement to provide some visual guidance.