All GPU have a memory.Generalized are 512 MB for the older beings... But now, not only that matters.My GTX 460 has as much memory than my 9400GT, and it's still a lot faster.So yeah, the fact that you don't need 250000 GB of RAM to do stuff also applies to GPU's .
Well keep in mind that the PS3/XBox 360's operating system is very small in size, therefore it doesn't take up much RAM.And I don't think MW3 runs on full settings on the console.
When it comes to GPUs, the architecture, design and clock rates of the GPU matters more than the memory. Most high end users go for 768MB+ anyway.
no, integrated graphics share with the rest of the system.and where did i say that was all that mattered wtf, i'm not handicapped. of course it's not all that matters. >.<