My laptop has an integrated GPU, but no discrete GPU. It is a MacBook Pro so I am running Mac OS X 10.6.8 (Snow Leopard). My CPU is Intel second-gen i5, and my GPU is the Intel HD 3000.
The way that I understand integrated GPUs is this: the GPU is attached directly to the motherboard, rather than being its own component, and it has no memory that is dedicated to the GPU. Since it has no dedicated memory, it has to "share" memory with the rest of the computer. And since it has to be shared, it cannot be accessed as quickly so that is usually why integrated GPUs perform slower than dedicated GPUs.
I've been looking for ways to improve my performance on games. Obviously I cannot buy a better CPU nor GPU since it is a laptop and there may be overheating problems. But I was thinking (please correct me if I'm wrong), since an integrated GPU "shares" memory, there is probably no physical restriction (contrary to having dedicated memory) so how much memory it can share - it is probably just a set number. So that leads me to my question: is there any way to raise the amount of memory that the GPU shares with the rest of the computer? Since many games use high quality models and textures, they require a lot of video memory. So if I could raise how much memory the GPU can allocate, perhaps I can gain a smoother experience. After all, when I play, I end up having about 1GB of memory that is unused since the bottleneck is typically the GPU, not the CPU.