# Is it possible to share Graphic card memory with RAM ?!



## Mohammed (Mar 8, 2012)

Hi every one 

I have this question in my mind from a long time 

Is it possible to share Graphic card memory with RAM ?


I mean I have PCI-E HD 4670 512MB and 4GB of RAM

So, Is that possible ?


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## cadaveca (Mar 8, 2012)

not really. It's kind of already done with certain GPUs, but outside of those products, no, it is not possible for end users.


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## Aquinus (Mar 8, 2012)

It also wouldn't help you a whole lot. Keep in mind that information needs to be transferred from the CPU, through the PCI-E bus, into the GPU and then into video memory. The latency between CPU and GPU Memory would make it slower than conventional memory since the GPU isn't using the memory. (GPU to VRAM is fast, CPU to VRAM is not, relatively speaking.)


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## Norton (Mar 8, 2012)

This link explains some of what I think you may be looking for (Windows virtual memory addressing as it applies to video cards/video memory)


http://www.techpowerup.com/forums/showpost.php?p=1323113&postcount=1

It is good info even if it doesn't specifically answer your question


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## Sasqui (Mar 8, 2012)

Norton said:


> This link explains some of what I think you may be looking for (Windows virtual memory addressing as it applies to video cards/video memory)
> 
> 
> http://www.techpowerup.com/forums/showpost.php?p=1323113&postcount=1
> ...



What Norton said (and Mussels sticky)!  Any memory sharing is through the system and drivers.  Some cards (like the X300) use system ram automatically, but only allocate a specific chunk.

Generally speaking, system ram is much slower to address from the GPU than the GPU ram itself.


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## Aquinus (Mar 8, 2012)

Sasqui said:


> What Norton said (and Mussels sticky)!  Any memory sharing is through the system and drivers.  Some cards (like the X300) use system ram automatically, but only allocate a specific chunk.
> 
> Generally speaking, system ram is much slower to address from the GPU than the GPU ram itself.



I don't think that was what he was asking. It sounded like he wanted to address GPU memory as system memory.


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## Norton (Mar 8, 2012)

Aquinus said:


> I don't think that was what he was asking. It sounded like he wanted to address GPU memory as system memory.



Op's question was fairly general so I steered him over to where some of his answers may be found....

Having windows 32bit in his sig with 4GB ram (3.25GB usable) he may have been asking if that unused system ram can be utilized for video ram as his card is only 512MB


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## DRDNA (Mar 8, 2012)

Normally this is only possible with integrated graphics.


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## Mohammed (Mar 8, 2012)

Okay 

So How I can do that

is there any program


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## W1zzard (Mar 8, 2012)

using system memory as additional gpu memory is already done for all recent cards (when they run out of on-board memory)

using graphics memory as system ram is not possible because the gpu mem lives on a different cache hierarchy and is much much slower to access.
it would be possible that someone writes a ramdisk that uses gpu memory and you put the pagefile on that. i don't know of any such software though


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## DRDNA (Mar 8, 2012)

Mohammed said:


> Okay
> 
> So How I can do that
> 
> is there any program



Well if you are really trying to add memory or reduce memory of the integrated GPU it would be done in the bios of the motherboard.
But that HD 4670 does NOT fit with in that scenario.


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## mudkip (Mar 8, 2012)

W1zzard said:


> using system memory as additional gpu memory is already done for all recent cards (when they run out of on-board memory)



Are you sure? So if a game uses more memory than my GPU has than it will use my system memory? Never heard of that before.


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## DRDNA (Mar 8, 2012)

mudkip said:


> Are you sure? So if a game uses more memory than my GPU has than it will use my system memory? Never heard of that before.



I am pretty sure with the 5000 series and up they do.


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## Aquinus (Mar 8, 2012)

DRDNA said:


> I am pretty sure with the 5000 series and up they do.








The 6870 has 1gb. This is perfectly normal. It's overflow. Keep in mind it doesn't actually use system memory unless it has to, but some video cards with less or when you start running games in eyefinity with only a little bit of video memory will need to swap memory in and out of system memory. You usually notice when this happens though.


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## OneMoar (Mar 8, 2012)

W1zzard said:


> using system memory as additional gpu memory is already done for all recent cards (when they run out of on-board memory)
> 
> using graphics memory as system ram is not possible because the gpu mem lives on a different cache hierarchy and is much much slower to access.
> it would be possible that someone writes a ramdisk that uses gpu memory and you put the pagefile on that. i don't know of any such software though



sounds like a job for a w1zzard


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## Aquinus (Mar 8, 2012)

OneMoar said:


> sounds like a job for a w1zzard



I could see it happening in linux, but I imagine it would have to be a kernel-mode driver.


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## xBruce88x (Mar 8, 2012)

at OP, you might be better off upgrading to x64 Win7. This way you can make use of all of your system ram, and that much more will be available if the gpu runs out of its VRAM.


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## W1zzard (Mar 9, 2012)

OneMoar said:


> sounds like a job for a w1zzard



i was looking into it but it's not worth it considering memory prices nowadays


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## OneMoar (Mar 9, 2012)

W1zzard said:


> i was looking into it but it's not worth it considering memory prices nowadays



awww here I thought I could put the extra 2GB of 320bit Gddr5 to work


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## Aquinus (Mar 9, 2012)

OneMoar said:


> awww here I thought I could put the extra 2GB of 320bit Gddr5 to work



The latency wouldn't be very good, but the bandwidth would be pretty good so I could see it being a good cache between system memory and your hard drive if it were done.


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## cadaveca (Mar 9, 2012)

OneMoar said:


> awww here I thought I could put the extra 2GB of 320bit Gddr5 to work



GPGPU work(F@H, BitCoin) already does...

Even using an IOMMU for an extra link isn't quite fast enough, but if you are using hte GPU for processing, that's a different situation entirely. The key is to make the value of the delay worthwhile.


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