I had LR 4 and was running happily on Windows 10. I subscribed to CC at the beginning of September and was using LR CC OK, but it did seem a bit sluggish. I have just come back from holiday and added 1,600+ images to the catalogue and the system just freezes anytime I try to do anything. Library is very slow and will only display a fraction of the thumbnails. As soon as I go to develop LR freezes.
I have just been back to LR 4 and that still works fine. At present CC is not workable.
Running on Intel quad core 3.1GHz 8GB RAM with Windows 10 Pro 64bit. All images are Nikon Raw lossless compressed at 10 to 20MB.
That's solved the problem. I have an AMD Radeon HD 7500 controller, which is in the Adobe site as having a problem, but fixed with the latest driver. I've just an AMD auto-detect on the latest driver and it seems that I have the latest released driver. It seems the new beta drivers are expected to address the problem.