Crossfire 7970 HELP!

I am planing to upgrade my rig with one more 7970

This is the rig after the upgrade:

Is the PSU powerfull enought for the system og do I need to get more power?

Thanks for the help :)

Yes, I am running 2 7950s on a 750watt, no problem you are fine.

I am curently runing one 7970 vapor-x and a 750 w PSU and I can't overclock my GPU!

When you crossfire you will not need too. Which software are you using to overclock?

It looks like you would PROBABLY be 'OK' for power, but I wouldn't chance it. I would look at an 850w+. It's better to get a bit more than you need with a good efficiency (80+ Bronze at LEAST) IMO. 

I'm running 8350 OC'd and 2 7970's with mild OC and I use a 1000w 80+ Gold.

The partspicker link says he will go 1000watt gold after upgrade thus my "hell ya" reply.

Sounds like you have a poor overclocking card.

Im crossfiring a 280x with a 7950 (yes. 7950). And im on a 650Watt. youll be fine.

Thanks everyone for the help :) I know what to do now