Is my power supply failing?

[Kavisha2]

My specs :-

Asus p8h67 m-lx
Core i3 2120 3.30Ghz
4GB ddr3 ram
820GB sata hard drive
power supply - Wixx 450 Watts (Korean brand)

I had an GT 740 1gb gpu. For this the system was running well
Recently i bought a new EVGA GTX 650 TI 1GB SSC
and the system was running well but when i play high demanding games like
ACU
ACS
Witcher 3
Mafia 3

it just freezes and comes back several times and after sometime a black screen appears or games
not responding. some time when the black screen appears i cant do any thing only to press the restart button.

My gpu and cpu temps are ok

gpu 32C-40C on windows
gpu 50C-65C while gaming

cpu - temps are normally 42C

Games doesn't even lags or slow down.
only this freezing thing.

I think its not a fault in the GPU
I think its a fault with my PSU which is Wixx 450Watts (Korean brand)

 

[MeanMachine41]

The only way to tell is to swap out the PSU with a known working unit of the same or higher Wattage.
You can test the unit under load by stress testing and using HWMonitor to monitor the 12V, 5V and 3.3V rails and that they are within spec. They should be within +or- 5% to be within spec.
Show your results if not sure.