Upgrading video cards. Do I need to also upgrade PSU?

[johnstac]

Currently I have a SeaSonic X-850 as seen here:

http://www.newegg.com/Product/Product.aspx?Item=N82E16817151102

Right now it is only running one SMI GTX 570 but I would like to remove it and upgrade to two Radeon HD 6990 as seen here:

http://www.newegg.com/Product/Product.aspx?Item=N82E16814102927

Will this one PSU suffice? Hoping so as it was expensive and I only bought it in January. Thanks in advance for any replies.

 

[Outlander_04]

http://www.hardwarecanucks.com/forum/hardware-canucks-reviews/41404-amd-radeon-hd-6990-4gb-review-21.html

They pull 469 watts at max load with one 6990 .

It might run for a couple of days with two of those things in it .

 

[Rizlla]

I would rather not chance it. Go for a 1000W or better 1200W PSU.

 

[mouse24]

wow, what kind of things do you need to do that requires 2x 6990s in there? 😀 but yes i would grab a higher wattage psu

Edit: now that i think about it, wouldn't 2x 6990s be ahuge waste of money since they are essentially 2 6950s slapped together?

 

[AdrianPerry]

From NewEGG: "750W Watt or greater power supply with two 150W 8-pin PCI Express power connectors recommended (1000W and four 8-pin connectors recommended for AMD CrossFireX technology in dual mode. 1200W recommended for optimal performance)."

So id say grab a new PSU $250 (after rebate) http://www.newegg.com/Product/Product.aspx?Item=N82E16817194092

 

[johnstac]

I wrote to Sapphire and they also said that I needed a minimum of 1000W. To the question about why I need two. I don't have to have two but I want to run eyefinity of three 27" monitors and I want everything at it's highest settings. I was going to originally run three 6950's but because I won't have room for the sound card, I decided to go with two 6990's which would allow room for the sound card as well?

 

[geofelt]

WOW! I did some checking for you.

AMD recommends 1000w to 1200w for dual 6990 cards!!
http://www.amd.com/us/products/desktop/graphics/amd-radeon-hd-6000/hd-6990/Pages/amd-radeon-hd-6990-overview.aspx#2

As a solution, you might consider an auxiliary psu for your system.
FSP has a 450w unit that fits in a 5 1/2 external bay that should add enough power for $90:
http://www.newegg.com/Product/Product.aspx?Item=N82E16817104054

 

[johnstac]

Okay, well I have since changed my mind on which video cards to use. Now I have decided on two of the GTX-580 3gb. I wrote to EVGA and they told me that I still need a 1000-1200w PSU. I had one on my shelf but I'm not sure I understand if it meets the requirements. The guy at EVGA told me that it needs to have at least 65a on the 12v rail. The one I have is here:

http://www.newegg.com/Product/Product.aspx?Item=N82E16817139007

Under details it states that it has two 12v rails with 40a on 1 rail and 40a on another. Will this work?

 

[avieor]

Okay, someone else has already asked you this, but I shall ask again.

What will you be using two 6990's for?
EDIT: Im sorry I didn't see your previous post.

And for the powersupply:
1500w
Silverstone 1500w
1200w
Corsair AX1200

 

[geofelt]

Okay, well I have since changed my mind on which video cards to use. Now I have decided on two of the GTX-580 3gb. I wrote to EVGA and they told me that I still need a 1000-1200w PSU. I had one on my shelf but I'm not sure I understand if it meets the requirements. The guy at EVGA told me that it needs to have at least 65a on the 12v rail. The one I have is here:

http://www.newegg.com/Product/Product.aspx?Item=N82E16817139007

Under details it states that it has two 12v rails with 40a on 1 rail and 40a on another. Will this work?

I am surprised, but check the label on the side of the psu.
On newegg, the up close photos show 500w as the maximum combined for the 12v rails. That equates to 500/12=41.6amps which is not nearly enough.
Such a meager proportion of 12v amps is surprising for a quality unit like Corsair. It is typical of older or cheap units.

Compare it to the PC Power and Cooling Silencer Mk II 950W which has 83a on the 12v rails.
http://www.newegg.com/Product/Product.aspx?Item=N82E16817703028

 

[avieor]

Here's the thing about eyefinity, If you are going to use 3 monitors, you would want 3 GPU's. 4 GPU's will only make it worse, adding microstuttering. I would tend to use 3x 6970's if you are going for a resolution of 7690x1440 ( 3x 1440p ) but if your monitors' resolution is 5760x1080p ( 3x 1080p ) I would then recommend 3 way gtx 580 SLI. I hope I was able to help.

 

[geofelt]

I am surprised, but check the label on the side of the psu.
On newegg, the up close photos show 500w as the maximum combined for the 12v rails. That equates to 500/12=41.6amps which is not nearly enough.
Such a meager proportion of 12v amps is surprising for a quality unit like Corsair. It is typical of older or cheap units.

Compare it to the PC Power and Cooling Silencer Mk II 950W which has 83a on the 12v rails.
http://www.newegg.com/Product/Product.aspx?Item=N82E16817703028

I have to amend my post.
I got to thinking about it, and revisited the psu spec plate diagram.
It is most unusual, in that the maximum 500w is for both a 12v rail and a 5v rail, but there is a second set that is also for a 12v and 3.5v set.
There is no way to break out exactly how much amperage there is available on 12v total.
You can expect that most of it is available for 12v, so the psu looks like it will handle the required 65a with ease, and be suitable for two GTX580's.

Go ahead and use the corsair hx1000.