Sure sounds like the cached data was used in your harddrive. If you copy/move files a lot and want performance, you'll want to get an SSD (solid state drive). If the computer you're using is the one in your signature, only type of ssd you can get is a SSD using a SATA3 interface. The newer NVME drives are not compatible with your system. Something like the Samsung 860 Evo is what you'd be looking at.