7970 Crossfire and PSU consideration

[masscrazy]

I have the MSI Lightning 7970 and am considering second Asus HD 7970 Matrix Platinum.

Couple of considerations - One will my PSU Corsair AX850 handle the two OC'd cards and overclocked i7?

Also will it and the lightning fit on my mobo?

http://www.asrock.com/mb/photo/Fatal1ty Z68 Professional Gen3(m).jpg

No hotlinked images. Thank you.

 

[breadturbo]

Your pushing it, a pair of ghz 7970s should be around 600w (full load) so up that for higher ghz.
A 3770k oc'd I believe is about 250w, some of the Quad boys should answer more definitely.

A big factor here will be how old is the psu?, capacitor aging will play a part in this.

Which i7 were you looking at, this is your 'official' list, so for a 3770k ensure you have bios P2.10
The lightning will work no problems.
http://www.asrock.com/mb/Intel/Fatal1ty%20Z68%20Professional%20Gen3/?cat=CPU

 

[masscrazy]

Your pushing it, a pair of ghz 7970s should be around 600w (full load) so up that for higher ghz.
A 3770k oc'd I believe is about 250w, some of the Quad boys should answer more definitely.

A big factor here will be how old is the psu?, capacitor aging will play a part in this.

Which i7 were you looking at, this is your 'official' list, so for a 3770k ensure you have bios P2.10
The lightning will work no problems.
http://www.asrock.com/mb/Intel/Fatal1ty%20Z68%20Professional%20Gen3/?cat=CPU

I already have the lightning and is clocked over ghz and the Asus will be well over a ghz 1300mhz possibly. And Intel Core i7-3770K.

I was wondering how the two dual slot and triple slot cards will sit on the mobo.

 

[Drangueos]

I already tested 2x HIS IceQ X2 7970Ghz edition at 1200/1700 and an i7 [email protected]... from the wall the max power draw was almost 800W so from the PSU was something around 650W.

You will be fine with a 850W psu.

 

[LtMatt]

750W for 7950 crossfire and 850W for 7970 crossfire would be my recommendations.

 

[setter]

750W for 7950 crossfire and 850W for 7970 crossfire would be my recommendations.

Id agree with this, the amd cards are a bit more power hungry than their nv equivalents. With a 4770k @4.5ghz and my 670's at +80, +600, max i seen drawn at the wall running 3dm11 was 586w, averaged around 520w. Psu is a 5 year old HX850, which im sure has lost a good bit of efficiency as it has powered several highly oc'd setups in that time.

Slot spacing on the asrock board looks very good for a multi gpu setup. This really helps with non ref cooler cards.

 

[Born_2_Kill_83]

I used to run a TX750W and had to upgrade when dropping in my CF7970GHZ, running stand GPU clocks was fine under that PSU (CPU O/C'd [email protected]). Soon as I O/C'd the cards I ran into some problems with games such as Metro LL and Crysis 3. Upgraded to a HX850 and the problems have gone away. I would recommend this PSU as a minimum if you want to OC CPU and 7970GHZ's.

 

[masscrazy]

Great stuff I've had the ax850 almost two years, but due to renovations my pc has been in storage for almost 9 months. So it should be good as new.

I'm currently running 1155mhz/1550mhz, if the matrix can go upto 1300mhz, what happens in xfire?

 

[Born_2_Kill_83]

I can't run no where near single card clock speeds in crossfire, my best is 1150/1700 CF, cant do 1175 but I can with one card. I game at 1100/1600 bullet proof stable and nearly as quick. Stability is what you need when gaming hours on end.