Alienware X51 R2 Not enough power?

Hello all.... so maybe someone could help me try to figure if I'm running low on watts here.

Alienware X51 R2 (330w  PSU)

i7-4790K (stock clock obviously)

8GB (4GBx2) DDR3-1600 RAM

Stock DVD/RW Unit

Intel WiFi 5300 Card

120GB Samsung  Evo 850 SSD

1 TB SATA 7200 RPM

PNY XLR8 GTX 970 (stock clocks)

On the USB ports:

- Logitech G930 headset (sometimes charging).

- JBL Pebbles USB Speakers

-  Logitech Illuminated Keyboard K740

- Logitech Unifying received (Performance MX Mouse) I charge the NiMH batteries elsewhere.

Problem:

Yesterday after about 3hrs of playing ARMA3 the computer shut off suddenly. I noticed the blue light on the PSU connection to the computer was off. I unplugged the PSU from the outlet and reconnected, the blue light came back on, the system restarted and has been running normal.

Are these symptoms of the 330W PSU not being enough? or the PSU is going bad?

Any ideas or thoughts? 

Thanks!