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ATI 3870 -- reference vs. non-reference PCB ??

Discussion in 'ATI' started by Beladi Nasrallah, Mar 3, 2008.

  1. ATI HD3870 was released by some Taiwanese and Chinese companies with
    non-reference printed circuit board (PCB) design. All of them are
    based on the non-reference PCB (developed by the Taiwanese
    manufacturer Triplex), e.g.
    http://www.unika.com.cn/index.php?o...d=3&task=viewproduct&productid=294&cataid=232

    The reference design card is shown e.g. in
    http://www.unika.com.cn/index.php?o...d=3&task=viewproduct&productid=290&cataid=232

    The non-reference card is shorter (7.4" vs 9" of the reference card),
    and it has the fan in the centre of the card, while the reference card
    has its fan at the distal end (away from the video connectors). It
    also seems to have fewer capacitors. The non-reference card occupies
    two PCI slots while the reference card has a one slot width.
    Powercolor, Colorful, Apollo, Unika and Triplex itself released the
    3870 card based on the non-reference PCB.

    Couple of months ago, I had a look at the website of a Chinese
    retailer. They sold the "reference" version of the card for around US
    $235, and the non-reference version for US$200. Obviously, the non-
    reference card is cheaper because it uses a cheaper PCB (was not
    bought from ATI) and fewer elements.

    So, here is my question: Is the image quality (for which ATI card are
    known) is worse in the non-reference version than in the reference
    version ? Where should I dig for such an information ? (Searching
    Google, MSN and Yahoo for answers did not bring anything up, and I do
    not think that the manufacturers will cough up the truth.)

    I am asking the question because I am attracted by the short form
    factor of the non-reference card, but I would not buying if it has an
    inferior image quality.
     
    Beladi Nasrallah, Mar 3, 2008
    #1
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  2. Beladi Nasrallah

    Guest Guest

    When a card is designed, every component on the card has a
    definite purpose. But when the card gets to manufacturing it
    goes through a "component reduction" process, where the
    company's bean counters decide what components really
    aren't necessary, and what components can be replaced by
    inferior/cheaper components.

    So the bottom line is, if you can find a video card model that
    looks true to the card's original design, it's almost certainly
    "better", in image quality, durability and probably both.
     
    Guest, Mar 3, 2008
    #2
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  3. Beladi Nasrallah

    Paul Guest

    The output on a GPU, is digital, up until the DAC. There is a DAC
    per gun. Eventually, you get the RGB output, in analog form.

    From the RGB signal pads, to the VGA connector, about the only other
    elements in the path, would be filter components. A basic VGA might
    use a simple inductor on the output. To control emissions, the
    filter might be modified, to be a PI filter (two SMT caps plus
    the inductor). That shapes the output spectrum (low pass filter).
    I've observed some video cards in the past, even had two stage
    filters. But I don't see an incentive for the redesigned board,
    to go crazy in that area. If you have high resolution photos of
    both boards available, you can examine the area near the output
    connectors, for three instances of filter components, and make your
    comparison there. A change in filter design, could cause slight
    fuzziness at super-high analog resolutions. At 1280x1024, the
    difference would likely be invisible.

    On the digital side of things, the visual quality should be unaffected.
    As far as I know, there aren't any additional components on the TMDS signals
    feeding the DVI-D side of the DVI connector. One datasheet mentions
    series damping resistors for TMDS, for EMI control, but all designs
    should stick to the same plan. (No big money saved by removing them.)

    So, other than some minor differences possible in the VGA, there
    probably isn't too much room for concern on fuzziness of image.

    The smaller card may forfeit -

    1) Compatibility with defacto standard cooler designs. The
    long card may have keepout zones, making room for various
    cooling options. You may want to compare the two cards,
    to see whether after market cooling is still possible.

    2) Power converter design differences. This is where a company
    can save a few bucks, by redesigning the power converters.
    The card converts 12V, to lower voltages like 1.8V or 1.5V etc.
    The GPU consumes many amps, which is why the converter is
    multiphase. Theoretical reliability could be affected. More
    than one power converter is used, as more than one voltage
    is needed.

    3) The shorter PCB saves the manufacturer some money. The layer
    count of the two PCBs could be different, but I doubt they'd
    change that. Sometimes, a minimum layer count is required, due
    to the needs in routing the breakout around the GPU. (The GPU has
    a lot of contacts on the bottom, and the copper tracks have
    to be routed out between them. More layers are added, to yield
    more routing channels for the copper tracks.)

    Review sites don't have the incentive, to analyze designs at
    that level. There have been the odd article, that looked at
    output issues (such as the issue with non-compliant DVI
    outputs on early DVI cards). But generally, all cards are
    treated as if they're equal now. (Just like nobody tests
    2D performance of video cards any more. They're all assumed
    to be the same.)

    HTH,
    Paul
     
    Paul, Mar 3, 2008
    #3
  4. Beladi Nasrallah

    First of One Guest

    Not necessarily. And prices from a couple of months ago are no longer
    relevant. I can't actually find a Triplex card for sale in North America,
    but Newegg sells the Apollo 3870 with the same short PCB and same cooler:
    http://www.newegg.com/Product/Product.aspx?Item=N82E16814140087

    It is listed at the same $190 price point as the Sapphire 3870 with the
    reference PCB:
    http://www.newegg.com/Product/Product.aspx?Item=N82E16814102719
    If you have an LCD connected via digital DVI (like most people do nowadays),
    then there would be no difference in image quality. If you have an analog
    monitor, then a cheaply-made card with cheap filters will give worse image
    quality. However, a mfr can use the reference PCB layout and substitute
    cheaper components on there at any time.
    Nobody evaluates analog image quality anymore, due to the prevalence of DVI
    monitors. The last review I've seen where this is evaluated
    semi-scientifically was written in 2001. Basically two reviewers looked at
    the monitor output and gave each card a score from 1 to 5:
    http://www.anandtech.com/showdoc.aspx?i=1507&p=4
     
    First of One, Mar 4, 2008
    #4
  5. Beladi Nasrallah

    KlausK Guest

    I used a Sapphire Reference 3870 and am using a Sapphire non-ref 3870. I
    like the non-ref better. It runs cooler and overclocks much better
    (currently running at 850/1200 with a Thermalright HR-03 GT Heatsink + a
    92mm Silenx fan; idle temp 35C, full load temp 46C).
     
    KlausK, Mar 4, 2008
    #5
  6. Beladi Nasrallah

    Carl Guest

    I am trying to run a reference and non reference 3870 in Crossfire, I have
    never had so many crashes before. I think that there must be a problem with
    the crossfire driver, if i turn off crossfire, games run ok. Crossfire
    enabled, after a short time, the monitor displays a chessboard corruption,
    sometimes crash to desktop, sometimes a total lock up. Hope the next driver
    update improves things, or one card is going on ebay for a pittance...
     
    Carl, Mar 5, 2008
    #6
  7. Beladi Nasrallah

    First of One Guest

    1. Make sure Catalyst AI is not disabled. This feature is needed for the
    driver to automatically select the correct Crossfire operating mode for each
    game.

    2. For troubleshooting purposes, run the game at 16x AA, which will force
    the Crossfire mode from Tiling to SuperAA.
     
    First of One, Mar 5, 2008
    #7
  8. Beladi Nasrallah

    Carl Guest

    Thanks, I'll give it a go!
     
    Carl, Mar 6, 2008
    #8
  9. Beladi Nasrallah

    Carl Guest

    Cat 8.3 seems to have cured most of the problems. The reference card is
    referred to as HD3870 in device manager, with the non reference card called
    HD3870 series. I tried Crysis on a 24" widescreen, and it ran ok on medium
    settings, game default.
     
    Carl, Mar 6, 2008
    #9
  10. Thanks, everyone, for your answers. Here I see two non-reference
    Radeon HD3870 cards for sale (same PCB). One of them (from Apollo)
    has only electrolytic capacitors, and another one (from Colorful) has
    only solid state capacitors. The question is, how bad is to have a
    video card with electrolytic capacitors ?

    I have done reading on the Internet, and it appears that good-quality
    electrolytic capacitors have a life span of 12-15 years. They degrade
    much quicker if exposed to heat. I imagine that such a card generates
    lots of heat... so that the capacitors will always be hot and may die
    quickly. How quickly ? I guess 5 years of life would be more than
    enough, 1-2 years would be a too short life.
     
    Beladi Nasrallah, Mar 9, 2008
    #10
  11. Beladi Nasrallah

    Flasherly Guest

    Sapphire used to be the OEM standard for meeting ATI-engineered board
    specifications. Not sure how that works since that last few years,
    though.

    http://www.newegg.com/Product/Product.aspx?Item=N82E16814102723
     
    Flasherly, Mar 9, 2008
    #11
  12. Thanks for your reply, but that was not my question. I am looking at
    an HD3870 card, and it has electrolytic capacitors in it. I am
    thinking: "Will this card last ? Or, should I be better looking for a
    card with solid-state capacitors ?"

    Here is what I found. Here is an article about the role of capacitors
    in videocard, http://www.dansdata.com/io070.htm (look for an article
    in the middle, titled "If it falls off, it isn't necessary"). It says
    that capacitors are used to smoothen the voltage spikes in the power
    supply line. The card will work without them, but will just be more
    susceptible.

    Here is another link, http://www.leadtek.com/eng/3d_graphic/overview.asp?lineid=1&pronameid=410
    .
    It gives you a table with an estimation of life time of electrolytic
    aluminium capacitor and aluminium solid capacitor in a video card
    Leadtek 9600GT. At a temperature of 85 C, the electrolytic capacitor
    has a life time of 8000 hours (the solid state has 20000 hours). This
    means that your videocard is good for 2000 days, or 5.5 years of
    gaming provided you play 4 hours per day. With a temperature of
    operation of 65 C, you get the lifetime 4 times longer. Phew. It seems
    that getting a videocard with all electrolytic capacitors is fine.
     
    Beladi Nasrallah, Mar 10, 2008
    #12
  13. Beladi Nasrallah

    Paul Guest

    If you were a real believer in reliability data, I think you'd be
    shocked, if you saw the calculated numbers for the GPU itself.
    Rather than worrying about the caps, I'd want to make sure my
    new video card had a good cooler.

    This document is a fairly easy read. It says there are a couple factors
    leading to failure. One factor is temperature related, and the
    empirical relationship is 10C cap temp reduction, doubles the
    lifetime. But after 15 years, the seal material may fail, so
    there is a wearout that prevents the cap from lasting forever.
    Presumably, you can find similar documents that discuss the
    multiple factors that might affect a solid cap. Be wary of
    simple minded marketing efforts...

    http://www.illinoiscapacitor.com/uploads/papers_application/85560DAA867C4AE2871F2EFA1749A6C7.pdf

    Electrolytic caps are fairly well understood, to the point that
    people can identify "cheating" in construction, just by looking
    at the devices. The rise in failures, due to bad electrolyte
    composition, in past years, was a departure from the norm, and
    didn't do anything for electrolytic caps reputation. It should be
    possible to build designs, where the caps last longer than the
    user is willing to continue using the card (due to obsolescence).

    So while a solid cap is "nice to have", it might not be the
    only thing that is unreliable on the card.

    Paul
     
    Paul, Mar 10, 2008
    #13
  14. Beladi Nasrallah

    KlausK Guest

    ..
    "It gives you a table with an estimation of life time of electrolytic
    aluminium capacitor and aluminium solid capacitor in a video card
    Leadtek 9600GT. At a temperature of 85 C, the electrolytic capacitor
    has a life time of 8000 hours (the solid state has 20000 hours). This
    means that your videocard is good for 2000 days, or 5.5 years of
    gaming provided you play 4 hours per day. With a temperature of
    operation of 65 C, you get the lifetime 4 times longer. Phew. It seems
    that getting a videocard with all electrolytic capacitors is fine."

    I have a Sapphire non-reference (blue) HD3870. With a Thermalright Heatsink
    attached, it never reaches 46C under full load (3D Mark 06) despite that
    it's OC'd to 850/1166. Your card will last for a long time.
     
    KlausK, Mar 13, 2008
    #14
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