Yes. Not only will a shared video RAM eat some main memory, but while the video chip is reading RAM for the display, the CPU can't read such space. An "hit" on CPU performance as well.
I would like to know something about GPU's.
now there are two kids of GPUs. There are the ATI and Nvidia graphics cards, with thier own dedicated ram, and then then there are ones like Extreme graphics from Intel that share RAM with the machine, and have no dedicated ram of their own. Now many people here and elsewhere point out that the grahics chips with their own dedicated ram are superior because they do not use up system ram.
But does it really matter?
How much of a dent would an intergrated graphics card like the Pentium Exteme grahics make on a systems ram when the system has 1000MB ram? So say you take 64MB out for the grahics, that still leaves 936MB for the system, so is that really that much of a dent?
Would it be fair to say that you can counter the disadvantage of not having a dedicated graphics card by simply adding more ram to the system?