When you swapped the power supply, Did you disconnect a case fan by any chance?
What case do you have. If it has not fans, Maybe it is time to add at least a rear fan to remove air from the case.
If the old power supply moved more air than the new one, things may run a bit warmer.
50c should not kill a hard drive.
The case is a GC X11 and it has ventilation in the back and front, never did have a problem with temps before.
I didn't disconnect any fans when swapping them over as far as I can tell.