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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  • johnsonx - Monday, May 14, 2007 - link

    and to which are you going to admit to?

    What was that old saying about glass houses and throwing stones? Shouldn't throw them in one? Definitely shouldn't them if you ARE one!
  • Puddleglum - Monday, May 14, 2007 - link

    quote:

    ATI's latest and greatest doesn't exactly deliver the best performance per watt, so while it doesn't compete performance-wise with the GeForce 8800 GTX it requires more power.
    You mean, while it does compete performance-wise?
  • johnsonx - Monday, May 14, 2007 - link

    No, I'm pretty sure they mean DOESN'T. That is, the card can't compete with a GTX, yet still uses more power.
  • INTC - Monday, May 14, 2007 - link

    quote:

    We certainly hope we won't see a repeat of the R600 launch when Barcelona and Agena take on Core 2 Duo/Quad in a few months....
  • Chadder007 - Monday, May 14, 2007 - link

    When will we have the 2600's out in review?? Thats the card im waiting for.
  • TA152H - Monday, May 14, 2007 - link

    Derek,

    I like the fact you weren't mincing your words, except for a little on the last page, but I'll give you a perspective of why it might be a little better than some people will think.

    There are some of us, and I am one, that will never buy NVIDIA. I bought one, had nothing but trouble with it, and have been buying ATI for 20 years. ATI has been around for so long, there is brand loyalty, and as long as they come out with something that is competent, we'll consider it against their other products without respect to NVIDIA. I'd rather give up the performance to work with something I'm a lot more comfortable with.

    The power though is damning, I agree with you 100% on this. Any idea if these beasts are being made by AMD now, or still whoever ATI contracted out? AMD is typically really poor in their first iteration of a product on a process technology, but tend to improve quite a bit in succeeding ones. I wonder how much they'll push this product initially. It might be they just get it out to have it out, and the next one will be what is really a worthwhile product. That only makes sense, of course, if AMD is now manufacturing this product. I hope they are, they surely don't need to make anymore of their processors that aren't selling well.

    One last thing I noticed is the 2400 Pro had no fan! It had a heatsink from Hell, but that will still make this a really attractive product for a growing market segment. Any chance of you guys doing a review on the best fanless cards?
  • DerekWilson - Wednesday, May 16, 2007 - link

    TSMC is manufacturing the R600 GPUs, not AMD.
  • AnnonymousCoward - Tuesday, May 15, 2007 - link

    "I bought one, had nothing but trouble with it, and have been buying ATI for 20 years."

    That made me laugh. If one bad experience was all it took to stop you from using a computer component, you'd be left with a PS/2 keyboard at best.

    "...to work with something I'm a lot more comfortable with."

    Are you more comfortable having 4:3 resolutions stretched on a widescreen? Maybe you're also more comfortable with having crappier performance than nvidia has offered for the last 6 months and counting? This kind of brand loyalty is silly.
  • MadBoris - Monday, May 14, 2007 - link

    As far as your brand loyalty, ATI doesn't exist anymore. Furthermore AMD executives will got the staff so you can't call it the same.
    Secondly, Nvidia has been a stellar company providing stellar products. Everyone has some ups and downs. Unfortunately with the hardware and drivers this is ATI's (er AMD's) downs.

    This card should do ok in comparison to the GTS, especially as drivers mature. Some reviews show it doing better than GTS640 in most tests, so I am not sure where or how discrepencies are coming about. Maybe hardware compatibility, maybe settings.
  • rADo2 - Monday, May 14, 2007 - link

    Many NVIDIA 8600GT/GTS cards do not have a fan, are available on the market now, and are (probably; different league) much more powerful than 2400 ;) But as you are a fanboy, you are not interested, right?

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