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I have a 1gig video card in a 32-bit system. I'd like to try running it with 512megs of RAM so my system can reclaim that 512meg. I doubt I need the full gigabyte of RAM on the video card. Is this possible?

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The chance that the 1 GB is shared memory (see rumtscho's answer) is very low, and thus it is RAM attached to the video card rather than the RAM on your mainboard. Thus there is no need to worry and you don't have to disable anything. – Tom Wijsman Jul 13 '10 at 14:38
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Clarification: In a 32-bit system only x amount of ram is addressable. The 1gig lowers my overall system ram, thus the question. It is not shared ram, but it does take away from the maximum available to the system. Currently at 2.8 or so when in other systems 3.2 or so is common. – overlord jr Jul 13 '10 at 15:24
even on a 64bt system only X amount of ram is addressable. your gpu-ram does not influence (or "take away") the ram attached to your mainboard. – akira Jul 13 '10 at 16:07
What OS? Most have 64 bit versions, linux and OSX have PAE kernels that address up to 64GB of virtual memory with a 32 bits userland. Your bios might have an option to change the AGP aperture size. – Tobu Jul 13 '10 at 16:30
@akira: he is right, I misunderstood him first. The gpu ram does not physically influence the system ram. But the address space of the cpu is shared between system ram, gpu ram and other addressable devices, so windows sees all of his gpu ram and only part of his system ram. – rumtscho Jul 13 '10 at 16:37
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3 Answers

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I understand what you're talking about (rumtscho and TomWij don't understand your question correctly), although I'm not sure how much of a performance increase you're going to see from having a few hundred more megabytes of RAM. Are you really using up all of that RAM all the time?

That said, if you really want that extra RAM, you really only have a few options:

  1. Use a soldering or desoldering iron to remove half of the RAM chips. You risk making the card completely nonfunctional if you do this incorrectly. Look and see if the chips are marked or numbered on the board. If so, remove half of the highest numbered chips (for example, if you have 8 RAM chips, remove 5-8 and leave 1-4). As long as you don't mess up the board when soldering, there's a fairly good chance that this would work. (Of course, most VRAM nowadays is surface-mounted TSOP or similar, which could be very difficult to desolder).
  2. Try to modify the BIOS or the card settings to disable some of the RAM. This is probably possible, but would require some hacking. You'd want to start by dumping the BIOS with a BIOS flashing program, then try to reverse engineer/disassemble the code and make modifications, then reflash the card with the modified BIOS. This is something the manufacturer almost certainly wouldn't approve of.
  3. Buy a card with less RAM, or try to get a friend to trade their video card with you.
  4. Get used to having less RAM. Maybe disable some startup applications, or try running a few less programs at the same time? It really isn't that hard to get along with 2.8GB rather than 3.2.
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To answer akira's question, the virtual address space is shared between the system RAM, video RAM, BIOS ROM, and other memory mapped devices. On a 32-bit system, that address space is limited to 4GB. So that means if your video card has 1GB of RAM, it will use up 1GB of address space, leaving 3GB (or less) still accessible for programs. So effectively, the less RAM the video card has, the more system RAM will be accessible. – Jesse Jul 13 '10 at 16:33
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up vote 3 down vote

Basically, there is nothing you can or need to do about it.

I don't quite understand if you have a real, separate video card or a "shared memory" video card (the latter is common in some laptops). Your first sentence sounds like it's separate, but the verb "reclaim" makes me think that you mean the second option.

In the first case, the RAM of the video card is not the same as your system RAM. They are not only different chips (the system one gets plugged into the mainboard, the video RAM is soldered to the video card), they are also different types of RAM. So there is no way to let the system use the video card RAM as additional RAM.

In the "shared memory" case, the video card doesn't have its own memory, and uses a part of the system memory for graphical purposes. But these cards are made smart enough. If this is what you have, your VC isn't always hogging a full gig of your system RAM, it only uses as much as it needs. So there is no need to do anything.

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In a 32-bit system only x amount of ram is addressable. The 1gig lowers my overall system ram, thus the question. It is not shared ram, but it does take away from the maximum available to the system. Currently at 2.8 or so when in other systems 3.2 or so is common. – overlord jr Jul 13 '10 at 15:13
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up vote 1 down vote

So far as I am aware there is no way to disable the video ram in an add-in video card. If you really need to recover the 512MB of RAM you will have to downgrade your video card.

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why leads the removal of 512mb of GPU ram to the recover of 512 mb of ram?? – akira Jul 13 '10 at 16:05
I'm guessing he doesn't need 1GB of video RAM but could use more system ram. – steve.lippert Jul 14 '10 at 14:42
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