AMD 690G is not a graphics circuit but a motherboard chipset, earlier known as ATI RS690. One of the main functions of AMD 690G is its integrated Radeon X1250 graphics core, which among others makes it possible to create cheaper and more energy efficient laptops, simply because you don’t need an external graphics card. It turns out that the K8 processors have had some problems entering a proper sleep mode when the motherboards have been equipped with integrated graphics circuits. Graphics circuits of K8 chipset namely has to fetch data and keep a constant connection with the shared RAM, which keeps the integrated northbridge of the processor awake.
This results in a not so efficient sleep mode and thus increase the power consumption, which no one wants. Therefore, AMD has decided to integrate an extra memory buffer with its motherboards so that the graphics circuit doesn’t have to access the RAM during sleep. It has also made sure that the chipset can switch to an external graphics circuit with those systems that wants to offers better 3D performance. This requires that the manufacturer installs an external graphics card though.
