I bought a new laptop, which had problems updating Windows 1803, after this, it was very slow, it only had programs installed: Office, google drive, onedrive and megasync. I thought it was a hardware problem and the store changed me for a new one.
Again I upgraded to 1803 and installed in the new laptop: office, onedrive, google drive and megasync and the computer is again very slow.
I'm not entirely familiar with the details of each of those cloud storage providers, but if one or more of them is set to sync certain folders, it seems logical to imagine that they might be encrypting and uploading or downloading and decrypting data to those folders to sync the drive's contents with an online mirror. It might be worth uninstalling those programs to see if performance is improved, then reinstalling them one at a time, to see whether one or more of them might be causing some performance overhead, rather than installing them all at once, making it more difficult to tell whether any one of them might be causing some problem. Did performance seem fine before installing this software?
It would also be worth checking task manager to see whether any of these programs are using a lot of CPU, internet bandwidth or drive access resources.