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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  • imaheadcase - Tuesday, May 15, 2007 - link

    quote:

    Bad performance with AA turned on (everybody turns on AA), huge power consumption, late to the market.


    Says who? Most people I know don't care to turn on AA since they visually can't see a difference. Only people who are picky about everything they see do normally, the majority of people don't notice "jaggies" since the brain fixes it for you when you play.
  • Roy2001 - Tuesday, May 15, 2007 - link

    Says who? Most people I know don't care to turn on AA since they visually can't see a difference.
    ------------------------------------------
    Wow, I never turn it of once I am used to have AA. I cannot play games anymore without AA.
  • Amuro - Tuesday, May 15, 2007 - link

    quote:

    the majority of people don't notice "jaggies" since the brain fixes it for you when you play.

    Says who? No one spent $400 on a video card would turn off AA.
  • SiliconDoc - Wednesday, July 8, 2009 - link

    Boy we'd sure love to hear those red fans claiming they turn off AA nowadays and it doesn't matter.
    LOL
    It's just amazing how thick it gets.
  • imaheadcase - Tuesday, May 15, 2007 - link

    quote:

    Says who? No one spent $400 on a video card would turn off AA.


    Sure they do, because its a small "tweak" with a performance hit. I say who spends $400 on a video card to remove "jaggies" when they are not noticeable in the first place to most people. Same reason most people don't go for SLI or Crossfire, because it really in the end offers nothing substantial for most people who play games.

    Some might like it, but they would not miss it if they stopped using it for some time. Its not like its make or break feature of a video card.
  • motiv8 - Tuesday, May 15, 2007 - link

    Depends on the game or player tbh.

    I play within ladders without AA turned on, but for games like oblivion I would use AA. Depends on your needs at the time.

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