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Thread: Radeon DRM Power Management Moves Along

  1. #31
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    Quote Originally Posted by RealNC View Post
    If you read a few posts above you will see that this has been answered already.
    I think it was question about reclocking info in AtomBIOS.

  2. #32
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    What about checking the lowest values used by fglrx and override atombios infos for RV670?

  3. #33
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    Quote Originally Posted by darkbasic View Post
    What about checking the lowest values used by fglrx and override atombios infos for RV670?
    First we have to know it's OK to downclock your memory. Maybe AtomBIOS tables are correct?

    Did you try fglrx? Does it report memory clock?

    Whatever we decide to do I suggest to wait for PM meeting in AMD. Now we just guess blindly.

  4. #34
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    Quote Originally Posted by Zajec View Post
    Did you try fglrx? Does it report memory clock?
    I used it for a while, but I didn't remember because I bought an Ati only for the open drivers. Surely the nvidia control panel do it.
    I can also boot windows and check the frequencies with some overclock utility.

  5. #35
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    On both Windows and Linux, when Catalyst downclocks my card (HD4870) for "non-3D mode" it only does that for the GPU. The memory clocks stay as they were.

    On Windows this can be seen in the "Overdrive" section of the CCC. On Linux you have to use fglrx's command line tool to get the clocks.

  6. #36
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    Quote Originally Posted by RealNC View Post
    On both Windows and Linux, when Catalyst downclocks my card (HD4870) for "non-3D mode" it only does that for the GPU. The memory clocks stay as they were.

    On Windows this can be seen in the "Overdrive" section of the CCC. On Linux you have to use fglrx's command line tool to get the clocks.
    AFAIK most of the HD 4xxx cards do not downclock the memory.
    Last edited by monraaf; 01-20-2010 at 01:08 PM.

  7. #37
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    Quote Originally Posted by monraaf View Post
    AFAIK most of the HD 4xxx cards do not downclock the memory.
    I don't think that's true. As far as I know, only the GDDR5-based HD4xx0 cards do not downclock memory, because GDDR5 memclock changes require some kind of recalibration that produces a short - but visible - flicker on screen.

    My GDDR3-based HD4850 downclocks memory correctly out of the box, which makes a visible difference in power consumption: with fglrx this card consumes around 40-45W on idle in my system (which can fall another 4-5W using a BIOS with reduced 2d memory clocks). With radeonhd (no power management), the same card consumes around 65-70W on idle - ouch!
    Last edited by BlackStar; 01-20-2010 at 01:18 PM.

  8. #38
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    Quote Originally Posted by BlackStar View Post
    I don't think that's true. As far as I know, only the GDDR5-based HD4xx0 cards do not downclock memory, because GDDR5 memclock changes require some kind of recalibration that produces a short - but visible - flicker on screen.
    Here's a review (in German) of the new HD 5670, if you scroll down a little bit you see a table with different cards, clocks and voltages.

    http://ht4u.net/reviews/2010/sapphir...670/index4.php

    As you can see all the HD 4xxx cards in the list have the same idle as load memory clocks.

    My GDDR-based HD4850 downclocks memory correctly out of the box, which makes a visible difference in power consumption: with fglrx this card consumes around 40-45W on idle in my system (which can fall another 4-5W using a BIOS with reduced 2d memory clocks). With radeonhd (no power management), the same card consumes around 65-70W on idle - ouch!
    Hmm, strange why your card does it and none of the GDDR3 ones listed in the review. A board difference or a Windows/Linux difference?

  9. #39
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    Hmm, strange why your card does it and none of the GDDR3 ones listed in the review. A board difference or a Windows/Linux difference?
    Different BIOSes come with different defaults, but in this case I think the table is incomplete or mistaken.

    For instance, my original 4850 BIOS contained three power states (2d, low 3d, high 3d), with 2d clocked at 750MHz and high 3d clocked at 993MHz (I think low 3d was 750MHz, too, but it's been while and I may be wrong). Later revisions of the card came with 2d at 500MHz, which prompted me to modify the BIOS manually.

    I don't think that's a windows/linux difference either, because my power meter gives the same indication on both OSes.

  10. #40
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    The tables look fine. How you interpret them and expose them varies based on the implementation. The kms code is pretty basic at the moment.

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