insufficient PSU?

[HankScorpio]

Hello I'd like some advice on whether my PSU is causing my system crashes.

It's a 500w antec I got from OcUK and it ran my last system spec just fine 24/7.

*old sys* phenom 955(1.4v), x2 5770s(1.1v each), 4GB ddr3 ram, x2 1.5TB HDD, SSD, dvddrive, gigabyte mobo and about 5 case fans.

Now I upgraded to a custom 7970, z77 mobo and i7 ivy @1.175v and using everything else.

I'm currently overclocking my 7970 and it needs around 1.2-3 volts to keep it stable.

While testing my card clocks at these volts my system just shuts off as if I'd pulled the power plug.

I thought it was an unstable clock, but I tested it at default clocks with just increased volts and it does the same, power cut effect.

Is it my PSU that's failing to supply power? This didn't happen in my old spec which I assume drew more power.

PSU problem or something else? Should I underclock/volt my cpu, pull my hdds and test my gpu at these volts to see if it doesn't crash?

 

[beejjacobs]

have you tried without the GPU and stress testing? It may well be the PSU, you're likely pushing it if you're overclocking.

Here is Guru3D's power supply recommendation:

Radeon HD 7970 - On your average system the card requires you to have a 550 Watt power supply unit.
Radeon HD 7970 Crossfire - On your average system the cards require you to have a 750 Watt power supply unit as minimum.

http://www.guru3d.com/article/amd-radeon-hd-7970-review/8

 

[HankScorpio]

What do you mean without the GPU stress testing?

I've prime95, IBT and I fold smp+gpu for hours on end with no crash, my CPU OC is stable. It's just when I try to increase the volts on my gpu it crashes.

I just restored my cpu to stock, removed all HDDs and case fans from psu and ran benchmark gpu test with increased volts and stock clocks and it crashes.

Could the temps be the cause? The card is nearing 100c when it crashes, though I've just put the gpu through an hour of heaven at stock volts and 1075/1450 clocks at it was around 95c just fine.

A bit bemused now since I don't think it's the PSU, maybe the card just doesn't like increased volts? Won't even run at 1.200volts