Add shared system mem to video card?

Discussion in 'Graphics Cards' started by failurbydesign, Feb 20, 2007.

  1. failurbydesign

    failurbydesign music MUSIC music Political User

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    Can this be done, my pc's on board graphics card has 126mb and my ati x700 pro has 256..like you see in the pic, it says total available graphic memory..or does that mean its using the 382?
     

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  2. loaderbull

    loaderbull OSNN Junkie

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    I have been wondering the exact same thing.

    I've a laptop with a 64MB Geforce Fx Go5200, but mine says i am sharing another 64MB from the system, totalling 128MB. Aero does run, quite smoothly in fact, although my laptop fan is always on, where in XP it isn't.
     
  3. ray_gillespie

    ray_gillespie Moderator Staff Member Political User

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    Loaderbull, I think yours is just using the shared memory of your RAM to act as video memory (you can set this amount in the BIOS - I remember a PC at work that was set to 256MB system RAM and 256 shared memory, when I set it to 1MB shared and 511MB system RAM it doubled in speed! [though would have been no good for games]/

    Failure, is yours a similar care or do you mean that your onboard graphics card has dedicated memory, which is being shared to your actual graphics card? That would be pretty cool!

    EDIT: That's a pretty cool backdrop you have! Where's that from?
     
  4. failurbydesign

    failurbydesign music MUSIC music Political User

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    Im not sure, my wallpaper is from the wallpapers from vista..
     
  5. loaderbull

    loaderbull OSNN Junkie

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    I assumed it was bios, but there aren't any options in mine...

    Only happens in Vista too, i have a dual boot with XP and Vista, XP is just 64MB of video.

    Cheers.

     
  6. fitz

    fitz Just Floating Along Staff Member Political User Folding Team

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    it's a "feature" of directX 10 called Virtualized Memory. Since DX10 is only in Vista, that would be why you don't see it on XP boxes.

    You can feel free to read through the Microsoft White Paper if you want to know more about it..

    The key point is that it uses system ram for video needs on as *as needed* basis. It does not reserve the system RAM exclusively for the GPU, meaning the "shared memory" value can be used by other applications and does not take away from your system RAM unless the graphics card needs more memory to run a task and even then, if the "shared memory" is in use by an application prior to the GPU requesting the memory, Vista will not release the memory for the graphics card.

    edit: think of the shared memory as "it's there if you need it unless something else on the computer is using it first"

    as for the original question on if the amount of shared memory can be changed, I'm not sure. It may be a function of the driver .. which would mean driver hacking.. I'll have to dig a little deeper and get back to you :)
     
    Last edited: Feb 20, 2007
  7. loaderbull

    loaderbull OSNN Junkie

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    Clever little feature that. Would be nice to be able to change it, especially seems as though i only have 64MB dedicated.

    Let me know if you find anything fitz,

    Cheers.

     
  8. fitz

    fitz Just Floating Along Staff Member Political User Folding Team

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    from my little bit of digging.. and actually reading the Microsoft Doc I linked to earlier, there is a formula to determine the maximum amount of RAM that can be setup as "shared memory" and is based on the total amount of system RAM (the various formulas are in the document)

    The driver (and whoever writes the driver) can change the amount of RAM setup as "shared" as long as it is below the hard max amount - meaning, there is an upper limit and the driver can set any value below that limit as "shared".

    As I am not a very accomplished writer of driver software (or any software really for that matter), I can't really tell you how to rewrite or hack the driver to change this amount. You would probably need to look at requesting such a feature through the card manufacturer and/or the 3rd party driver manufactures like the Omega drivers.

    edit: Here is a link with a little more info and a more readable explaination
    http://blogs.msdn.com/pigscanfly/archive/2006/10/10/Grahiphics-Memory-Reporting-In-Vista.aspx
     
    Last edited: Feb 21, 2007
  9. loaderbull

    loaderbull OSNN Junkie

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    Excellent.

    I shall be reading that later, thanks fitz.