Power Supply Requirements

With new product launches, we expect to see increased power requirements for increased performance. With the 8800 series, we saw hardware that offered excellent performance without breaking the bank on power, while the highest end part available required two PCIe power connectors. We can forgive the power gluttony of the 8800 GTX as the 8800 GTS offers terrific performance with a more efficient use of power.

R600 goes in another direction. We have a new part that doesn't compete with the high end hardware but has even more stringent power requirements. While NVIDIA's $400 hardware offered good power efficiency, AMD's Radeon HD 2900 XT eats power for breakfast. In fact, with the R600, we see the first use of PCIe 2.0 power connectors. These expand on the current 6-pin power connector to offer up to 150W over an 8-pin configuration.

The 8-pin PCIe 2.0 power connector enables graphics cards to pull up to 300W of power just for themselves. With 75W delivered through the slot, 75W through a 6-pin PCIe power cable, and 150W sliding down the PCIe 2.0 wire, the R600 has plenty of juice on tap. While it doesn't pull a full 300W in any test we ran, overdrive won't be able to function without the combination of a 6-pin and 8-pin connector.

All is not lost, however, as two 6-pin connectors will still be able to power the R600 for normal operation. The 8-pin receptacle will accept a 6-pin cable leaving two holes empty. This doesn't degrade performance when running R600 at normal clock speeds, but overclocking will be affected without the added power.

The bottom line as we'll shortly show is that AMD has built hardware with the performance of an 8800 GTS in a power envelope beyond the 8800 Ultra. We will take a closer look in our performance benchmarks when we actually test power draw under idle and load using 3dmark06.

The Test

CPU: Intel Core 2 Extreme X6800 (2.93GHz/4MB)
Motherboard: EVGA nForce 680i SLI
ASUS P5W-DH
Chipset: NVIDIA nForce 680i SLI
Intel 975X
Chipset Drivers: Intel 8.2.0.1014
NVIDIA nForce 9.53
Hard Disk: Seagate 7200.7 160GB SATA
Memory: Corsair XMS2 DDR2-800 4-4-4-12 (1GB x 2)
Video Card: Various
Video Drivers: ATI Catalyst 8.37
NVIDIA ForceWare 158.22
Desktop Resolution: 2560 x 1600 - 32-bit @ 60Hz
OS: Windows XP Professional SP2
Sapphire's HD 2900 XT Battlefield 2 Performance
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  • Roy2001 - Tuesday, May 15, 2007 - link

    The reason is, you have to pay extra $ for a power supply. No, most probably your old PSU won't have enough milk for this baby. I will stick with nVidia in future. My 2 cents.
  • Chaser - Tuesday, May 15, 2007 - link

    quote:


    While AMD will tell us that R600 is not late and hasn't been delayed, this is simply because they never actually set a public date from which to be delayed. We all know that AMD would rather have seen their hardware hit the streets at or around the time Vista launched, or better yet, alongside G80.

    First, they refuse to call a spade a spade: this part was absolutely delayed, and it works better to admit this rather than making excuses.



    Such a revealing tech article. Thanks for other sources Tom.
  • archcommus - Tuesday, May 15, 2007 - link

    $300 is the exact price point I shoot for when buying a video card, so that pretty much eliminates AMD right off the bat for me right now. I want to spend more than $200 but $400 is too much. I'm sure they'll fill this void eventually, and how that card will stack up against an 8800 GTS 320 MB is what I'm interested in.
  • H4n53n - Tuesday, May 15, 2007 - link

    Interesting enough in some other websites it wins from 8800 gtx in most games,especially the newer ones and comparing the price i would say it's a good deal?I think it's just driver problems,ati has been known for not having a very good driver compared to nvidia but when they fixed it then it'll win
  • dragonsqrrl - Thursday, August 25, 2011 - link

    lol...fail. In retrospect it's really easy to pick out the EPIC ATI fanboys now.
  • Affectionate-Bed-980 - Tuesday, May 15, 2007 - link

    I skimmed this article because I have a final. ATI can't hold a candle to NV at the moment it seems. Now while the 2900XT might have good value, I am correct in saying that ATI has lost the performance crown by a buttload (not even like X1800 vs 7800) but like they're totally slaughtered right?

    Now I won't go and comment about how the 2900 stacks up against competition in the same price range, but it seems that GTSes can be acquired for cheap.

    Did ATI flop big here?
  • vailr - Monday, May 14, 2007 - link

    I'd rather use a mid-range older card that "only" uses ~100 Watts (or less) than pay ~$400 for a card that requires 300 Watts to run. Doesn't AMD care about "Global Warming"?
    Al Gore would be amazed, alarmed, and astounded !!
  • Deusfaux - Monday, May 14, 2007 - link

    No they dont and that's why the 2600 and 2400 don't exist
  • ochentay4 - Monday, May 14, 2007 - link

    Let me start with this: i always had a nvidia card. ALWAYS.

    Faster is NOT ALWAYS better. For the most part this is true, for me, it was. One year ago I boght a MSI7600GT. Seemed the best bang for the buck. Since I bought it, I had problems with TVout detection, TVout wrong aspect ratios, broken LCD scaling, lot of game problems, inexistent support (nv forum is a joke) and UNIFIED DRIVER ARQUITECTURE. What a terrible lie! The latest official drivers is 6 months ago!!!

    Im really demanding, but i payed enough to demand a 100% working product. Now ATi latest offering has: AVIVO, FULL VIDEO ACC, MONTHLY DRIVER UPDATES, ALL BUGS I NOTICED WITH NVIDIA CARD FIXED, HDMI AND PRICE. I prefer that than a simple product, specially for the money they cost!

    I will never buy a nvidia card again. I'm definitely looking forward ATis offering (after the joke that is/was 8600GT/GTS).

    Enough rant.
    Am I wrong?
  • Roy2001 - Tuesday, May 15, 2007 - link

    Yeah, you are wrong. Spend $400 on a 2900XT and then $150 on a PSU.

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