Microsoft this week announced a new feature for Windows known as CASO (Cross Adapter Scan-Out). This new feature is designed for laptops with hybrid graphics. CASO aims to improve performance and efficiency when alternating between integrated and discrete GPUs.
Enhancing GPU Efficiency with CASO
Cross Adapter Scan-Out (CASO) focuses on optimizing the efficiency of hybrid GPU configurations, common in modern laptops, incorporating both an integrated GPU (iGPU) and a discrete GPU (dGPU). The conventional approach involves using the iGPU for display and lighter tasks, while the dGPU handles more demanding tasks like gaming and rendering.
Traditionally, laptops rely on proprietary solutions, such as NVIDIA’s Advanced Optimus and AMD’s Smart Access Graphics, utilizing a Multiplexer (MUX) chip to switch between iGPU and dGPU based on the workload.
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However, these solutions are limited to specific vendors and hardware, leaving other laptops without this optimization.
The CASO Advantage: Efficient GPU Utilization
Microsoft’s Cross Adapter Scan-Out addresses this gap by enabling efficient GPU switching without requiring a MUX switch. In the absence of a MUX switch, two copies of a rendered frame are sent out—one from the dGPU to a shared resource and the other from the shared resource to the iGPU (for display).
While functional, this approach results in lower FPS and higher latency.
We first released CASO with support for DirectX 11 in 2021 and expanded its reach to DirectX 12 during early 2023, which means that CASO now supports almost all PC games.
In our tests, on a select set of popular PC games, we observed an average of ~16% FPS increase1 and ~27% display latency reduction. In addition, CASO contributed to a 45% decrease in timeout detection and recovery events (TDRs).
— Microsoft
With CASO, only one copy of the rendered frame is required, directly scanned out to the display, maximizing performance by utilizing the most suitable GPU for the task at hand.
This eliminates the need for shared resources and MUX switches, leading to improved performance, reduced display latency, and enhanced battery life.
The Impact of Cross Adapter Scan-Out (CASO)
Microsoft’s internal tests have demonstrated the positive impact of CASO on GPU performance and efficiency, showcasing significant benefits:
- Average 16% increase in FPS (Frames Per Second)
- 27% reduction in latency
- 45% decrease in Windows TDR (Timeout Detection & Recovery Events)
These impressive results indicate that Cross Adapter Scan-Out is a promising solution for enhancing GPU utilization in hybrid laptops, making them more efficient and capable of delivering an improved user experience, especially during gaming and resource-intensive tasks.
Wide Hardware Support and Game Compatibility
Microsoft has ensured that CASO supports a broad range of hardware configurations and is compatible with both DX11 and DX12 titles, underlining its commitment to versatility and compatibility across the gaming spectrum.
In conclusion, Microsoft’s Cross Adapter Scan-Out is set to redefine the efficiency and performance of hybrid laptops by optimizing GPU usage, eliminating the need for proprietary solutions, and offering a seamless GPU-switching experience for a more efficient and enjoyable computing experience.
What Microsoft Partners Have To Say About CASO
- AMD
“As a testament to our long-standing partnership and commitment to technology innovation, together we made hybrid graphics better for gamers, delivering more frames per second and lower latency. CASO is available starting on AMD RyzenTM 6000 Series processors with RadeonTM graphics, the most advanced processor in its class for high-end gaming on ultrathin notebooks.”
- Intel
“Intel strives to improve gaming performance and CASO delivers such improvements with reduced frame latency and increased FPS with our integrated and dedicated GPU offerings”.
- Nvidia
“All currently supported NVIDIA GeForce GPUs support CASO starting with driver version r515_00.
The latest GeForce Game Ready Driver is available for download here.”
