I have read somewhere, that setting fixed pagefile size causes the drive to write in the same place all the time and increases wearoff of those particular SSD cells

I have the same problem as author, started a new thread, currently freeing up some space at C: partition improved my performance, but not to the original state. I have fresh 8.1 pro install, I use no 3rd party antyvir (just Defender), almost no services running, no application open and getting folder opening times 2-3 seconds... its ridiclous :/