12. Dedicated Graphics RAM And An Integrated Graphics Processor?

Naturally, the combination of Shared Memory or also Unified Memory Architecture (UMA) and dedicated graphics RAM with an integrated graphics core isn't as fast or efficient as a stand-alone graphics processor with its own dedicated graphics RAM.

Up to 256 MB of memory can be dedicated to handling graphics.

Overall, integrated graphics controllers deliver noticeably fewer pixel pipelines and vertex shaders as compared to their dedicated cousins. In addition, the graphics kernel must share memory bandwidth with the CPUat least, for those frame buffers allocated from Shared Memory. Then too, dedicated graphics RAM usually runs at a higher clock rate, and offers much lower latency compared to conventional RAM, thanks to shorter leads between the graphics chip and dedicated graphics RAM.

The hybrid format that HP uses in its Pavilion dv8000z seeks to take advantage of the best of both worlds, while also seeking to consume the smallest amounts of power. To keep power consumption in the graphics subsystem low and thereby extend battery life as much as possible, the graphics driver in this notebook comes equipped with PowerPlay 5.0, which is designed to minimize and manage its power draw.

Energy-saving functions in PowerPlay can drastically reduce power consumption in the notebook's graphics subsystem.

The Radeon Xpress Mobile Graphics driver supports two speed options: Optimal Battery Life, with the GPU clock set at 100 MHz, and Optimal Performance Mode, where the graphics core runs at 300 MHz. Through Dynamic Lane Count Switching (DLCS) the graphics subsystem achieves the necessary 3D calculation performance while reducing power consumption. This is achieved because when the graphics subsystem is only lightly loaded, individual lanes in the PCIe bus simply shut down, even when running in performance mode.

The system accesses the dedicated video RAM using a so-called SidePort. If a 128 MB dedicated frame buffer isn't sufficient for some needs, an additional 128 MB of shared memory from the system RAM can be switched into this memory pool.