Question HDD Crashing

[m0v1c]

Hi all, this is my first post. I recently switched my primary HDD to a 256GB SSD. When I did this I moved all my steam games + photos/videos to a spare mechanical HDD. Since then the HDD tends to crash during gaming or even just while being used for a screen saver repository. Sometimes it will crash to desktop and other times the drive disappears all together from windows explorer. A simple reboot normally fixes this but not always. I have tried changing SATA ports and cables. Just yesterday I tried a new HDD with same files but same result while playing Rainbow seige and Slime rancher. I was thinking to put all files and OS onto a new 1TB SSD with OS but wanted to know if this was a motherboard issue or something else....?
These are my specs:
WIN 10
MB ASUS P8H61 PRO
Intel i7-2600 CPU @ 3.4GHz
8GB DDR3
256 SSD
1TB HDD
GC Asus Nvidia GTX 660ti
Any ideas would be appriciated!

 

[Dark Lord of Tech]

I would get a separate SSD for all the games and other files , leave OS on the 256GB.