GTX 960 PSU problem

[Beriman]

Hello!
I need your help, because I don't know, if it is normal.
I have recently changed my GTX 550 Ti card to a Asus GTX 960 Strix 2Gb OC used card. It ran normally, everything was fine until I started a Game, when the PSU (M-tech 450w) started buzzing, and restarted the PC. I was concerned about the PSU problem. The next day I have bought a brand new Chieftec 500 W PSU. Now it works even under heavy load, but even the new PSU buzzes lightly, when a demanding game is on.
Even though I think 500 W is enough for my system, I am not sure this is "healthy".
What do you think? Shall I be worried?
My specs:
Fx-6300
GTX 960 2Gb
8gb Ddr3 ram.

 

[Dark Lord of Tech]

Wattage is enough , but both PSU's are very poor quality.

 

[Beriman]

Wattage is enough , but both PSU's are very poor quality.

Will it do any damage to my system?

 

[Dark Lord of Tech]

I personally wouldn't use either of them. Not worth risking damage to the rest of your setup.

 

[wallpleases]

What exact model PSU did you get?

 

[Beriman]

I personally wouldn't use either of them. Not worth risking damage to the rest of your setup.

What exact model PSU did you get?

I've got the Chieftec I-arena GPA-500S8 supply

 

[Beriman]

Now I had another restart, but with the Chieftec PSU, under heavy load it also Buzzes. What PSU should I try next?