With speedfan, use 'config' tab to uncheck or turn off the 120 degree temp readouts with the orange flame designation. Those reading are measuring nothing and defaulkt to 120. The PSU would not directly effect the FPS. If the uniut is shutting down randomly, there may be a shorting issue or other hardware related issue, but it is not because the CPU is 120c. That is a false reading.
Is this rght mate?