Vista - 2-Card SLI Question

Any tool can be inaccurate if not fully understood and use correctly. Not saying you didn't but....

Also, If he has a good quality 600w power supply, he could run those two cards just fine, especially if he's not pumping power to an excess of other items - waterpumps, a host of fans, 3-4 hard drives, multiple CD/DVD drives, or heavy overclocking.

Just my two cents

we need to read all the posts we seem to be repeating each other

I thought the video cards were measured with Amps more than Wattage? I had 1 GTX260 + 1 8800GT and my 600W Thermaltake ToughPower (top of the line PSU from Tt) was not capable of handling it or was just barely able to push them because of the low amperage on the 12v rail.

Opinions vary on power supplies when it comes to pure wattage, but there's more to it than that. In addition, you also have to consider you electricity bill when running these things.

Personally I think the average gaming system probably doesn't require more than an efficient 650watt PS.

This...
Intel Core i7 965
ASUS P6T Deluxe
6gig Corsair TR3X6G1600C8D Dominator RAM
Creative X-Fi Titanium Fatal1ty Pro Soundcard
A pair of ATI 4870x2 in Crossfire mode or a pair of Nvidia GTX 295's in SLI mode

Is NOT a "typical" gaming system, and these are the systems that benefit from something more than 650watts

Reading reviews and gaining an understanding on how PS work has made me rethink the wattage wars and reinforces my total agreement about purchasing a quality power supply.

This is the conclusion on a review of my Antec "550" watt - Antec NeoPower 550 Power Supply Review | Hardware Secrets. Note that this "550" watt is capable of producing 650watts!

And ATI has certified this power supply for crossfiring two 4850's - ATI Radeon™ HD 4890 - System Requirements.

Here's a good article about selecting a power supply - TweakGuides.com - Hardware Confusion 2009. Scroll down to “Power Supply”

It's not always about wattage, it's also build, design, and efficiency. How to Buy a Power Supply: 7 steps - wikiHow

And lastly here's the recommended power supply wattage for two 4890's in crossfire mode -

  Quote: Originally Posted by AstaLaVista

I thought the video cards were measured with Amps more than Wattage?

Yes, and it has to do with the total amps the +12v rail system is capable of delivering. If a power supply isn’t designed well, it will shut off with a high amperage demand. That's why some people talk about balancing a load across multiple rails - See here: Antec NeoPower 550 Power Supply Review | Hardware Secrets, the paragraphs after fig 20.

At any rate that's my two cents for the way I see things.