Why am I experiencing hard drive issues during more intense reading operations?

My 14TB Exos internal HDD started restarting itself during more intense reading operations on it. E.g. showing the thumbnails in a folder with 400 JPEGs in it: about 20-70 thumbnails will load, then the HDD makes the noise it makes when the PC boots (i.e. the HDD powers up) and it stops loading them. After it powers up again in a few seconds, the next ~20-70 more thumbnails will load and then it will restart itself again and so on. No data was lost, HD Sentinel shows 100% healthy and all green, the HDD itself is about 9 months old. Changing the SATA slot, SATA cable, or power cable of the HDD

Question by jedivader on Super User, licensed CC BY-SA. We show a short excerpt and link to the original thread as credit.