Minimum PSU for 2x7970?

[Daragh]

Really the title describes it, guru-3D recommends at least a 750w (which I have). Going down the radeon route as I bought a Motherboard without SLI support.

A few things- I am going to run multi-monitor, I currently have 3 fairly low end screens but with a little saving hope to get 3 of the Benq XL2420T, rest of PC is coming up to scratch, don't trust my sig.

My current PSU: http://www.pccasegear.com/index.php?main_page=product_info&products_id=15350

System will have to deal with

i5 3570k (overclocking purposes, if I fry its cheap to buy)

8gb Mushkin redline

Asrock Z77 Mobo

Cooling isn't really an issue as I'll integrate into a W/C loop

Won't overclock graphics card though the CPU would get a boost

So really, is a 750watt enough for my system (in 7970 crossfire)

if not, what would two 7950's draw. And what performance difference

I know its probably a no-go but any input would be nice

[IVIYTH0S]

Lol at the cpu comment, can I have one since they're so cheap

 

but that's a good unit so I'd give it a whirl, I think with stock 7970s and overclocked chip you should be ok

http://www.guru3d.com/article/radeon-hd-7970-crossfire-review/7 567W

http://www.techpowerup.com/reviews/ASUS/HD_7970_CrossFire/22.html 525W

http://www.legitreviews.com/article/1834/11/ 641W

http://www.kitguru.net/components/graphic-cards/zardon/his-hd7970-crossfire-review/17/ 514W

 

And mind you these figures are probably from the outlet so factor in the conversion losses and the numbers will be a bit lower yet (and the fact that some of these setup may have more power hungry CPUs)

[d6bmg]

A good 650 Watt PSU would be sufficient for your case.

Choice of PSU will depend on your taste and your requirement.

[Muchoman1]

better safe than sorry, get the 750w, i have always been a fan of going slightly over on PSU to keep the load on it down, and most units are less efficient above 80% load.

 

As for power draw, 7950s will only draw slightly less than 7970s, stick with the 7970s and get a 750w psu

[IVIYTH0S]

better safe than sorry, get the 750w, i have always been a fan of going slightly over on PSU to keep the load on it down, and most units are less efficient above 80% load.

 

As for power draw, 7950s will only draw slightly less than 7970s, stick with the 7970s and get a 750w psu

And 7950s seem to draw more overclocked too (possibly due to the 7970s having higher binned GPUs?)