Microsoft offers a solution “Basic problem of modern hybrid laptops” In this context, “hybrid” refers to laptops equipped with both integrated and discrete graphics. They can work together to improve power efficiency by distributing the graphics load between each other depending on complexity. However, the use of this combined System has its disadvantages.
In laptops with hybrid graphics, the integrated graphics unit (iGPU) of the CPU is usually connected directly to the laptop’s display. Discrete graphics cards (dGPU/eGPU), in turn, have the task of processing visual effects, which are then transferred to the iGPU for display on the laptop screen. This scheme allows you to achieve a balance between graphics performance and energy efficiency. Resource-intensive tasks are shifted to discrete graphics cards to improve performance, and energy costs are reduced thanks to the iGPU, whose job is to display graphics on the screen.
For games that require higher graphics performance, the bottleneck with this design is the iGPU, which can prevent individual graphics from reaching their full performance potential. Technologies such as NVIDIA Advanced Optimus and AMD Smart Access Graphics use a multiplexer (Mux) to solve this problem. This allows you to transfer all tasks in games to the dGPU and only use the integrated iGPU for everyday tasks. This feature eliminates the need for data transfer between the integrated and discrete GPU, ensuring maximum gaming performance.
However, not all laptops are equipped with a hybrid graphics subsystem with a multiplexer, which leads to an increase in the overall power consumption of the system. In this case, the image drawn by the discrete graphics processor is still sent through the iGPU to be displayed on the screen. This creates bottlenecks and is unlikely to have a positive impact on performance.
The “Cross Adapter Scan-Out System” (CASO) software function developed by Microsoft simplifies the operation of the graphics subsystem of laptops that do not have a multiplexer or of laptops on which it is not activated. CASO allows you to ignore the presence of integrated graphics and transmit the image drawn by a discrete GPU directly to the screen. This results in improved graphics performance and reduced display latency.
Microsoft says that on average, FPS (frames per second) increases by 16% and display latency is reduced by 27% when using CASO. Additionally, this software feature reduces the number of TDR (Timeout Detection and Recover Events) or graphics driver timeouts by 45%, making laptops more stable overall.
“We first released CASO with DirectX 11 support in 2021 and added support for DirectX 12 in early 2023. This means that CASO is now supported on virtually all PCs.” In our tests with a selection of popular PC games, we saw an average increase in FPS of 16 percent and a reduction in latency of 27 percent. In addition, CASO reduced the number of driver timeouts by 45%.”the company says in its blog.
According to Microsoft, the technology is already part of the Windows 11 operating system. The company said CASO will work with all GeForce GPUs that use driver version r515 or later. The Intel platform requires an 11th Generation or higher Core processor with integrated Intel Xe graphics and WDDM 3.0 driver or higher. AMD requires a Ryzen 6000 series processor or higher with Radeon graphics and WDDM 3.1 driver or higher.