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Thread: ATi Radeon 2600 PRO 512mb - Linux recognize it as 256mb

  1. #1
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    Default ATi Radeon 2600 PRO 512mb - Linux recognize it as 256mb

    I have an Asus EAH2600PRO 512mb on a media pc connected to a TV with HDMI cable. I recently discovered that the OS (Xubuntu 13.04) recognize it as 256mb only GPU.

    The gart.size setting is set by default to 512 as it should.


    The display is a 1080p one so i really need those extra MB of RAM on this old GPU in this resolution.

    Why is this happening and what should i do to make the OS recognize it as 512mb GPU?

    Thank you.

  2. #2
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    The 256MB number probably refers to CPU-accessible memory, since that's the limit of the PCI BAR. The GPU can access all 512MB.

  3. #3
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    Quote Originally Posted by bridgman View Post
    The 256MB number probably refers to CPU-accessible memory, since that's the limit of the PCI BAR. The GPU can access all 512MB.
    When i enabled Steam "Big Picture Mode" i got this warning: "Your display device has only 268,44 MB of dedicated GPU memory. You are likely to have poor performance at 1080p"

    System profiler & benchmark tool also "Memory 256MB (prefetchable)"

  4. #4
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    IIRC VRAM detection via Steam (or the code used in Valve games, not sure) is a separate issue. Thought there was a known problem there but I'm having zero success finding any details on it. I'm sure it's been discussed here before, don't remember if there was a resolution though.

    EDIT -- do you have a "Primary VRAM not detected" message in the Steam system information ?
    Last edited by bridgman; 07-12-2013 at 09:26 AM.

  5. #5
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    Yes i do get "Primary VRAM not detected".

    Steam at Display settings (big picture mode) refers to the GPU as X.org 256 MB.

    I really don't care so much about Steam itself if it is detecting the VRAM correctly. I care about the OS itself. As i said "System Profiler & Benchmark" is detecting 256MB too.

    Is there any better way to display VRAM info more accurate?

    Thank you again.

    EDIT: with
    Code:
    lspci -vv
    i got 256MB prefetchable too..
    Last edited by verde; 07-12-2013 at 12:34 PM.

  6. #6
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    Check your dmesg output, that will tell you how much vram is on your card, You should see something like:

    Code:
    [    1.874683] radeon 0000:00:01.0: VRAM: 512M 0x0000000000000000 - 0x000000001FFFFFFF (512M used)
    [    1.874685] radeon 0000:00:01.0: GTT: 512M 0x0000000020000000 - 0x000000003FFFFFFF
    [    1.874688] [drm] Detected VRAM RAM=512M, BAR=256M
    [    1.874689] [drm] RAM width 32bits DDR
    [    1.874807] [TTM] Zone  kernel: Available graphics memory: 3829974 kiB
    [    1.874813] [TTM] Zone   dma32: Available graphics memory: 2097152 kiB
    [    1.874816] [TTM] Initializing pool allocator
    [    1.874826] [TTM] Initializing DMA pool allocator
    [    1.874886] [drm] radeon: 512M of VRAM memory ready
    [    1.874891] [drm] radeon: 512M of GTT memory ready.
    - lspci
    lspci only show the PCI apertures (BARs) which are limited to 256MB. This is the CPU's window into vram (the maximum amount of vram that can be mmaped by the CPU). It does not represent the amount of vram on the card (the GPU can access the entirety of vram). This may be what "System Profiler & Benchmark" looks at. I'm not sure what "System Profiler & Benchmark" is.

    - steam
    OpenGL does not provide a way to query the amount of memory available. Applications have to use use vendor specific extensions or guess based on vendor strings or pci ids. Steam probably defaults to 256MB if it can't figure out something better.

  7. #7
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    Quote Originally Posted by agd5f View Post
    This may be what "System Profiler & Benchmark" looks at. I'm not sure what "System Profiler & Benchmark" is.
    It is Hardinfo 0.5.1, Ubuntu Dash and Software Center calls it as "System Profiler and Benchmark"

    dmesg output solved my curiosity. VRAM 512MB BAR 256MB.

    Thank you all for your assistance.

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