"256MB of DDR3 SDRAM shared with main memory"?

[antster94]

Hey guys,

Just wondered as I'm thinking of ordering a 2.66 Refurb 13" MBP. Whats the difference between having 256MB of DDR3 SDRAM shared with main memory and 256MB memory? Does it mean that I'll just have less RAM available to use?

Sorry if it's a dumb question, don't know a lot about hardware.

Anthony

 

[Hellhammer]

Shared memory means that it uses your RAM. For example, if you have 4GB of RAM, 256MB of that will be dedicated to the GPU thus you have only 3.75GB for other stuff. Discrete GPUs that can be found from 15" and 17" have their own GDDR integrated into the graphics card

 

[antster94]

Ok cool thanks Hellhammer.

 

[rockstarjoe]

I was just wondering the other day where a quarter of a GB of my memory was going... thanks for the info!

 

[WardC]

Hellhammer answered this very well. When you have shared memory for the graphics controller, like on my Mac Mini, instead of showing that the machine has 2GB of RAM in Activity Monitor, it shows that I have 1.75GB of RAM. 256MB is shared for the graphics controller. The 15" and 17" MacBook Pro have a dedicated discrete nVidia graphics card with its own memory on the graphics card, so the CPU can take full advantage of 100% of the installed RAM in the machine. No shared memory.