Q: Late 2009 iMac Ram/Vram Please Help

See:http://www.everymac.com/systems/apple/imac/specs/imac-core-2-duo-3.06-21-inch-al uminum-late-2009-specs.html the maximum VRAM for that model is 256 MB.

The specs noted by Everymac say the NVIDIA graphics chip model share memory, but typically, Macs that use memory sharing can only go above the specified graphics memory if the system memory has been maxed out.  So you will have to raise your system memory from 4 GB to at least the Apple specified limit of 8 GB to see an increase in useable graphics memory.  If you do that, be aware that iMacs are very sensitive to their memory, it must be exactly in line with the Apple specs, not PC memory.  Only buy the memory from a reliable Mac supplier like OWC, http://www.macsales.com or Crucial, http://www.crucial.com

I have this same model iMac installed with the complete 16 GBs of RAM.

That stated, some users that have this model iMac reported that their late 2009 iMacs would crash with the total 16 GBs of RAM installed.

Many users or the late 2009 iMac models reported they could install 12 GBs of RAM with no stability issues.

There is no way to tell which late 2009 models had the issue with installing the total 16 GBs of RAM.

The GPU is NOT upgradeable and iMacs, generally, use discrete GPUs and NOT shared RAM GPU types.

Legendarysuperfreak wrote:

 

For clarity.  If I maxed out my RAM at 16g I'll have 512mb of vram but that's the limit and I need to be very specific when purchasing RAM?

No.

You would need to have the 512 MB VRAM nVIdia GPU installed in your iMac for this to work. As Ralph Landry 1 has pointed out, your model iMac can only have the 256 MB VRAM GPU.

Hi Ralph,

I have this iMac year and model with full 16 GBs of RAM and my GPU is the 256 MB VRAM GPU. With a full compliment of RAM, there is no where in my system profile that says my GPU VRAM can go to 512 MB or exceed the 256 MB Limit?

I have no clue what you are trying to convey.

Are you saying that if that model iMac needs more than the specified fixed 256 MB VRAM, the OS X will allocate some of the installed RAM to the GPU?

How can that be possible with a discrete GPU?

Here is some info from a couple of very lengthy threads re. the RAM issues for late 2009 to late 2010 iMacs - the point was mostly that you could go to 16 GB, but only if you went with OEM RAM; with 3rd party RAM, it was best to stick with a max of 12 GB.

Problem with 16GB on 2010 iMac 27" i5 & i7.

New 27" 2010 iMac i7 Memory Issues

I have a mid 2010 and decided to play it safe and installed 2 x 4 GB (in addition to the OEM installed 2 x 2 GB) for a total of 12 GB - from OWC.

I don't believe you can increase your VRAM - in the specs here, it simply shows that it was available with two different graphics cards:

iMac (21.5-inch, Late 2009) - Technical Specifications

And the following specs mention "maximum" VRAM = 256:

http://www.everymac.com/systems/apple/imac/specs/imac-core-2-duo-3.06-21-inch-al uminum-late-2009-specs.html

Thank you, babowa!

Everything you posted is exactly what I thought all along.

Good to see you back here.

Hope you are doing fine.

Thanks - doing well!