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Will 2x 7950's fit on my Mobo?! :[

Greeny93

Greeny93

Greeny93

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Believe it has to be slot 1 and 3 for 2 way CF/SLI but an X79 expert will answer for definite.

You don't need to match cards in CF/SLI so you could get one of those cards, place it in the bottom slot and get a different one for the top slot thus ending all problems about spacing :).

750W should be OK for that set up but SB-E chips do tend to consume a lot of power as will two 7950s over volted. What PSU? You may need to get an 850W but if it's a good 750W it will be fine.
 
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Presumably, you'd out the cards in slots 1 and 5 and have the sound card in 4, Atleast that's how it works with my ROG mobo.

Try checking the manual to see what it says.

As for PSU, what make and model?

Have you considered the Giga wind force cards? I'd recommend them over these as they have better CS, however, the WF cooler dumps all the heat into the case, so good airflow is paramount.
 
Thanks for the replies -
According to my mobo manual... Dual graphics need to be in slots 1 and 4. Though I don't know if this is the only possible arrangement? :/

The Power supply is a competitors own brand 80+ "Black edition" The psu was a bit of a last minute buy without too much research xD

... Can the soundcard fit into a regular PCIe slot? With it being, don't know the technical term... " not a full length pcie " :s Persumed it could only fit in slots 2 & 6 ( PCIe 2.0 x1 )

I did look at the Giga ones, the exhaust's on the HIS sounded better though?! My case does have amazing air-flow, though it sounds like a Jet :]
With decent airflow, the Giga's are a better buy, then? hmm.

Cheers again.
 
I would definitely get a new one then if you're going to be running a SB-E with two 7950s. Although can you tell from the label on the PSU how many amps on the 12V rail(s) it supplies?
 
Yes thanks :)

Eek. That's only 216W per rail. Not the greatest. :)

Could you just take a picture of the label to clarify? It looks like a new PSU is in order though. Not the most exciting thing to spend money on I know but it will help to keep your components safe.

This is a good model:

http://www.overclockers.co.uk/showproduct.php?prodid=CA-039-CS&groupid=701&catid=123&subcat=1084

As are the XFX ones but OcUK is out of stock.

http://www.overclockers.co.uk/productlist.php?groupid=701&catid=123&subid=1497

You can probably comfortably get away with 750W but as you're more than likely going to be recommended to get a new one, you may as well pay the bit extra to get an 850W. I'm not 100% sure on the power consumption of the 3820 combined with two 7900 series while all overclocked but pgi has a similar set up so hopefully he'll see this thread and post his own findings.

The main problem with your power supply is that the power is split over multiple rails and none of the rails supply much power individually so it will be messy and complicated to ensure than a single rail doesn't become overloaded etc.
 
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AC Input ------------------100-240V ~ 10A 50/60Hz
DC Output --------------+3.3V +5V +12V1 +12V2 +12V3 +12V4 -12V +5Vsb
Max Load ---------------28A----30A---18A----18A---18A---18A---0.8A 3A
Max Combined Wattage ----180W-------------650W-----------9.6W 15W
Total Power 750W

If that helps? :p Massive amount of effort taking a photo! :(

Hmm, Thanks for the advice Rusty... Say the powersupply isn't up to the job, whats the concequences? :o Explosionssssss? or just, shut-downs?

Don't really fancy shedding out more cash, if it can be helped!
 
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Does it have 4 PCI-E cables?

If so can you tell if the cables are going to different rails? (normally colour coded or labelled)
 
Yes it does :]

All 4 PCIe's are the same colour - Red =/

I'm afraid i'm little to no help, really don't know anything to do with "rails" :((
 
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Greeny93 said:
Yes it does :]

All 4 PCIe's are the same colour - Red =/

I'm afraid i'm little to no help, really don't know anything to do with "rails" :((
Click to expand...

Basically, the 12v rails are the ones we're concerned about as those are the ones that'll power the gfx card and CPU etc.

To find out what wattage the PSU actually is, you multiply the amps by the volts. So, in your case it's 18A on each 12v rail, so 18x12=216w per rail.

Realistically, this means each of your rails will be able to support one graphics card/CPU.

If you had 2 7950's on a single 12v rail with 18A, then you'd probably cause some sort of failure. However, if you had each 7950 on a different rail, it would probably be fine :)

That being said, you probablyh should get a new PSU, just to be safe. Silverstone, XFX, Corsair and Seasonic are the ones I personally tend to look at :)

As for which coolers on which card to get, it's really debatable. I personally believe that going for coolers which exhaust heat into the case is fine if you have spacing between them and good airflow as these coolers are often quieter than 'leaf blower' coolers which exhaust heat out of the case. The downside when using 2 of these is that the top card tends to get maybe 10-15 degrees hotter than the bottom. However, depending on the GPU and the cooler, this isn't a massive problem IMO. For me, my 7970 Lightnings reach about 70 under full load and 65 for the bottom card, staying realtively quiet. Most certainly quieter than some single card setups using reference coolers! :)
 
Thanks for the advice Clecoooo... LAST question('s)

I'm really not bothered about noise from the Gpu's as my rig already sounds like a turbine engine. So, ignoring noise, which would be the better option? :p & remembering I have a Soundcard at the bottom which will be near flush with the bottom card =/

& the Powersupply, if say my psu isn't up to the job, whats the concequences? ;o will it go pop or just shut-down? any chance of damaged components?

Thanks!
 
Hopefully, it'd either just commit PSU suicide, or it'll just keep shutting down... you never know though :eek:

Ignoring noise... that's tough. I would still rather go with the windforces, mainly due to CS, bt also because I can't imagine they'll fair much worse than the HIS'

Also, they only take 2 slots, so it may advantageous if you change plans in the future.

Have you checked what your mobo manual says in regard to 2 card xfire?
 
This takes me back to my original questions xD

Mobo is all good with xfire - Slots 1 and 4. This leaves ample room between cards, ( 3 slots ) BUT the soundcard goes into slot 6, only leaving 2 slots for the bottom card :/

The HIS's are slighly bigger than the windforces aren't they?

This is all so complicated ;p
 
whyscotty said:
No, it means slots 1 and 5 for dual card set ups
Click to expand...

this :)

When numbering the slots, it's referring to the pcie 16x slots. The 2nd slot is a pcie 1x so isn't included in that.

So, you gfx will go in slots 1 and 5. That means your sound card will go in slot 4.

This also means you can get the HIS cards, depending on whether your case gives you enough clearance for it.

I think you can use the other slots, but it's recommended you use thoe ones they tell you.
 
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