Power supplying 4 Radion HD 6990

I'm the latest person registered on this site until now

I'm selling my laptop ASUS G73jh and building my first gaming station, but I've encountered a PSUs issue. Briefly this' my story:
I've just received my Gigabyte 990FXA-UD7, Mushkin 2X4GB DDR3-2000 CL9 and a Corsair Force3 120GB SSD.
My next thing on the list are 4 Gigabyte GV-R699D5-4GD-B and PSU's.
In a month I will buy the AMD's eightCored Bulldozer (for now I will use Sempron 140 2.7Ghz, it's the cheapest CPU in my country )
I'll buy some huge sata3 HDD too.

The thing is I'm not sure what PSU's to take. I thought about taking 4 of 500W for each GPU and one 1000W for the motherboard, but I'm pretty sure I'm making a mistake here and it won't be enough for this kind of monster. That's why I'm referring this question to you guys, PRO's in this stuff.
Surely I'll overclock that beast and for general information, I'll make a mineral oil aquarium with a few ThermoElectric Coolers and Oil Fans.
This will be my modest self 23rd birthday gift

So what suggestions do you have for right wattage of PSUs for this station?

P.S: Any other suggestions will be very welcome too.

Im pretty sure you cant run 4 6990's in the same rig...
The 6990 is a dual core gpu.

For 3d use you can only use up to four GPUs, and a 6990 is two GPUs on one card.
Hence you're stuck with just two 6990s.

If you're using them for number crunching rather than 3d stuff you can have as many as you want.

I will use it for 3 main purposes: gaming, multimedia editing, and when it's idle it will number crunch.
From all I read until now, there are bios updates for running up to 8 GPU cores.

So, you have any suggestions on how to supply this PC?

The maximum power draw of any PCIE video card should be 250W, IIRC (75 watts from the slot, 75 watts from a 6-pin, 100 watts from an 8-pin). I very much doubt that they'd be able to overclock high enough to need 500W. The video cards would only be using 12V power, so you would want to get as many amps on 12V as possible. A couple of good 750W, each powering two cards, should be more than enough for a decent overclock at full draw.

For the main system, 1000W would be far beyond overkilling overkill squared. The video cards are the major draw, and if they're on a separate source, then 500W would be more than plenty.

So if I want the PSUs to work on 80%-90% I'll need about 900W per couple.
But I don't get why on Gigabyte site they write that one card needs 750W?

And why do you think that they are bad at overclocking?

Thanks for reply

Nogard said:

But I don't get why on Gigabyte site they write that one card needs 750W?

Click to expand...

Because lots of power supplies are crappy, and say they have more power than they actually do.

Nogard said:

And why do you think that they are bad at overclocking?

Click to expand...

You're going to let the magic smoke out before you manage to get them to eat double their rated power, unless you're planning to join the liquid N² people

AMD.com:

The AMD Radeon™ HD 6990 graphics card features dual-BIOS capabilities. This feature is controlled by the Unlocking Switch, which toggles between the factory-supported Performance BIOS of 375W (BIOS1), and an Extreme Performance BIOS (BIOS2) that can potentially unlock higher clock speeds and up to 450W of mind-blowing performance!

Click to expand...

375*4=1500
450*4=1800

Now if you're going to flip the BIOS switch and overclock, I'm not so sure how you're going to dissipate all that heat.

What I would do is get these two. The 1200W will power three cards and the 750W will power the rest of the system + one card.
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139014&Tpk=AX1200
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139016&Tpk=AX750

If you're going to go with the 450W profile, I'd go with a 1500W and a 850W.
http://www.newegg.com/Product/Product.aspx?Item=N82E16817256054&Tpk=ST1500
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139015&Tpk=AX850

If you need to save money, the Corsair AX750 and AX850 also come in HX (modular) and TX (hardwired) models. Lower efficiency though.

We will see that...

And thanks for information.

About the heat, I'm planning an aquarium that will hold oil in low temperaturesof about 20 degrees... not sure though exactly.



Hope that OC members won't be disapointed in me

Well, we certainly cant call you un-ambitious. Good luck.