The Card and The Test

The Radeon HD 4830 reference board we tested is based on a revised design put together for this part, but AMD built this chip to be able to fit into existing 4850 board designs as well. The maximum power envelope is the same, but actual power usage will be lower. AMD has informed us that initial boards based on the 4830 will be using 4850 boards, but that down the line we should start seeing boards based on the more compact 4830 reference design.

As for how the GPU stacks up against some of the other offerings from AMD, here's a handy chart:

  ATI Radeon HD 4870 ATI Radeon HD 4850 ATI Radeon HD 4830 ATI Radeon HD 4670
Stream Processors 800 800 640 320
Texture Units 40 40 32 32
ROPs 16 16 16 8
Core Clock 750MHz 625MHz 575MHz 750MHz
Memory Clock 900MHz (3600MHz data rate) GDDR5 993MHz (1986MHz data rate) GDDR3 900MHz (1800MHz data rate) GDDR3 1000MHz (2000MHz data rate) GDDR3
Memory Bus Width 256-bit 256-bit 256-bit 128-bit
Frame Buffer 512MB/1GB 512MB 512MB 512MB
Transistor Count 956M 956M 956M 514M
Manufacturing Process TSMC 55nm TSMC 55nm TSMC 55nm TSMC 55nm

Based on the information we know about the GPU, the 4830 is clearly just an RV770 with two SIMDs disabled. While AMD does have safeguards built into their GPUs to help improve yield, nothing is perfect. There will be ICs that come off the line that simply can't function properly at the desired speed or with all the hardware enabled to make it onto a higher end card. Chip makers will save these parts and bin them for possible use in lower end products later. We also sometimes see higher end binned chips released as special editions overclocked models, so it does work both ways.

The price of the 4830 means that it will see higher volume sales than either the 4850 or the 4870. That's just how it works: more people buy cheaper parts. The interesting twist here is that the RV770 is being used in 3 different parts ranging from $130 to $300 with very little time lapse between the initial release and the current situation.

While we still would really love to see a top to bottom launch on day one of a new architecture some time, this is very impressive in it's own right. The delay between the launch of the 4870 and the 4830 is likely due to the fact that AMD needed to maintain enough supply to meet demand for it's two higher end parts while steadily building up a supply of chips for use in the 4830. As demand will be higher, stockpiling chips that can't run at 4830 specification for a few months will certainly help meet the needs of the market.

Now that we know what we're testing, let's take a look at our test platform.

Test Setup
CPU Intel Core 2 Extreme QX9770 @ 3.20GHz
Motherboard EVGA nForce 790i SLI
Video Cards ATI Radeon HD 4870
ATI Radeon HD 4850
ATI Radeon HD 4830
ATI Radeon HD 4670
NVIDIA GeForce GTX 260 core 216
NVIDIA GeForce GTX 260
NVIDIA GeForce 9800 GTX+
NVIDIA GeForce 9800 GT
Video Drivers Catalyst 8.11 Beta
ForceWare 178.24
Hard Drive Seagate 7200.9 120GB 8MB 7200RPM
RAM 4 x 1GB Corsair DDR3-1333 7-7-7-20
Operating System Windows Vista Ultimate 64-bit SP1
PSU PC Power & Cooling Turbo Cool 1200W
All About Price and Rebates Age of Conan Performance
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  • nirolf - Thursday, October 23, 2008 - link

    That low core/mem looks promising. It would be interesting to see if you can get close to 4850 with some tweaking. Reply
  • Mathos - Thursday, October 23, 2008 - link

    And I think I found my next video card upgrade. Have been either waiting for the 4850 to drop a bit more, or something to come out between the 4670 and 4850 to come out, and this one hits exactly where I figured it would. Nipping at the heels of the 9800gtx in a few benchies there, and at the Res that matters for me 1680x1050. This looks like something I can pair with my 3870 toxic edition till I can afford a full on 4850 or 4870. Then if I wanted to I can get rid of the 3870 and run Xfire with the 4830 and 4850. Reply
  • DXRick - Thursday, October 23, 2008 - link

    The charts for power consumption are totally different (show a lot more consumption, especially at idle) than the charts done for the 4670 article: http://www.anandtech.com/video/showdoc.aspx?i=3405...">http://www.anandtech.com/video/showdoc.aspx?i=3405... Reply
  • JarredWalton - Thursday, October 23, 2008 - link

    From the other article: "At idle our entire testbed (Intel G45 + Core 2 Quad Q9450) used only 67W with the Radeon HD 4670." Note that this article uses QX9770 and 790i, among other differences. Reply
  • DXRick - Friday, October 24, 2008 - link

    I had no idea that different chipsets (or mobos) and cpus could result in such a dramatic difference in power consumption. I sure want my computer to consume as little as possible when I am not using it.

    Are there any other articles here about this?

    Thanks!
    Reply
  • strikeback03 - Monday, October 27, 2008 - link

    http://www.anandtech.com/casecoolingpsus/showdoc.a...">http://www.anandtech.com/casecoolingpsus/showdoc.a... Reply
  • Jovec - Thursday, October 23, 2008 - link

    More importantly, all your previous reviews show roughly a 40+ idle and load watt difference between the 4850 and 4870, yet this review has it down to 3-4 watts at both. Was there a problem with 4870 power consumption that has now been fixed? Reply
  • Jovec - Saturday, October 25, 2008 - link

    And now these 4850 and 4870 numbers show a wider margin again. With a different testbed I'd expect different numbers, but the relative difference on the same testbed should be the same. These numbers are more in line with AT's other 4850/70 power numbers. The original article's numbers need to be explained. Reply
  • JarredWalton - Thursday, October 23, 2008 - link

    I believe that was one of the issues with previous Catalyst drivers: for some reason the power saving stuff wasn't working on 4870. It's good to see that finally addressed. Reply
  • Jovec - Thursday, October 23, 2008 - link

    Seems likely for idle numbers, but I'd be curious what power saving can be done under load. Reply

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