GTX 580 Phantom SLI

That power supply is going to be cutting it close. I've been toying around with an appliance load tester on my machine (see signature). During windows operations, my machine runs around 250W. I regularly run from 700-800W when gaming with 2 580s. I'm running 2 HDD and 1 SSD. Which 850W PSU are you using? The spec for a standard 580 is 244W. Yours will probably use slightly more due to additional requirements for the RAM and possibly due to the added fans. As a result (using W/V), you also need to make sure you have at least 20-22A/card and another 10-12A for the processor on the 12V rail. You should target 56A+ on a single 12V rail or make sure you have at least 22A available on each 12V rail over multiple rails (depends on the PSU).

Additionally, I would suggest a 950W+ PSU to account for the inefficiencies of aging capacitors and other aging equipment in your system over time.

The additional RAM on the cards will probably draw a little more power, but nothing substantial.

Yes i figured 850 would be very close to limit so i cutted some budget here and there to make space for a corsair AX 1200 which, i read, has good ratings. Everyone is welcome to suggest a better one.

I'm affraid the space is gonna pose the bigger problem. I still gotta place the order so i had no "field" experience with the parts but the Phantom is rated 2.5 slots. I've a dedicated audio card which would need a pci and i'm not sure everything is gonna fit on the Maximus IV Extreme if i get 2 phantoms. Anyone has advice?

Ah. I found a good picture of the side of these things:

http://vr-zone.com/articles/vr-zone-exclusive-gainward-...

3 slots it is. Is any motherboard made to accommodate two of these plus other devices?

How do you feel about on-board sound?

It's not an issue to use the on-board one but i'm not comfortable excluding 2 slots just to fit a bigger (as good as it might be) cooler. I think i'm gonna get a pair of MSI 580 twinfrozr II or is there any better option (excluding water cooled ones)?

I like my PNY cards because of the limited lifetime warranty and because I could return them directly to the Microcenter a few miles from my house if there was anything wrong with them out of the box. I have a tendency to seek out this convenience with the higher-priced parts.

3yrs parts/2 yrs labor is decent with the MSI cards and they're at a 800MHz core. Gigabyte has one with almost the same spec (795MHz core) with three big fans and heatpipes and a 3/3 warranty. I had some Gigabyte factory OC'd 5850s which had the three fans and similar heatpipes. They ran 10C cooler than my HIS 5850 with standard cooling. Based on that experience, I'm guessing they offer decent cooling on the 580 as well.

Judging from this image i was thinking if it's possible to set a triple slot one on PCIEX16_1 (the first from right) which whould take up to PCIEX16_2 (the third from right) and a second triple slot one in PCIEX16_4 (the fifth from right) which would take up to, well, out of the mobo i guess? Also, would this configuration, if possible, run at x8/x8?

Best answer selected by LoneHertz.

This is true if you're going with 3 cards. I have a system with two 580s and regularly reach the 750s when I measure wattage with an appliance load tester on my system while playing MOH. I've never seen it higher than that. 3 580s would definitely require additional power. Going with 3 cards, I'd recommend a 1100W PSU, at least, because you're potentially adding a requirement of an additional 264W (at max load) for an additional 580. If I'm already at 750+ adding a 3rd card (at max load) would require at least 1014W! WOW!

Nope. Nothing is overclocked. The 580 cards require up to 22A on the 12V rail each.