Hardware Reference
In-Depth Information
with a brand-new shader design, Shader Model 4. Shader Model 4 adds a geometry shader to the
vertex shader and pixel shader design used in earlier shader models to improve the handling of real-
time scene changes such as explosions. However, the biggest single change in Shader Model 4 is the
use of unified shaders that can be switched between vertex, pixel, and geometry shader operations on
the fly, eliminating bottlenecks and improving performance, no matter what types of 3D data exist in a
scene.
Note
With the replacement of dedicated vertex and pixel shaders in the DirectX 10 3D rendering
pipeline, DirectX 10 GPUs are rated in terms of the number of stream processors on board.
Each stream processor performs vertex, geometry, and pixel shading as needed.
When you are comparing two otherwise-equal DirectX 10 GPUs (same GPU, memory size and
speed, motherboard and memory bus designs), the GPU with a larger number of stream
processors will be faster.
Other architectural changes in DirectX 10 include process optimizations to reduce the load on the
CPU. In a sample of different types of images rendered, DirectX 10 reduced the command cycles by
as much as 90% over DirectX 9.
DirectX 11 was originally developed for Windows 7 (and is also available for Windows Vista) and
adds several new features:
•
Tessellation
—Provides additional pipeline stages that increase the number of visible polygons
at runtime.
•
Multithreaded rendering
—Enables the execution of Direct3D commands on multiple
processor cores.
•
Compute shaders
—Provides an additional stage independent of the Direct3D pipeline that
enables general-purpose computing on the graphics processor, part of Shader Model 5. This
feature is supported by the processor with integrated graphics.
•
Dynamic shader linkage
—A limited runtime shader linkage that allows for improved shader
specialization during application execution.
To obtain a version of DirectX 11 for Windows Vista, see KB971512 at
http://support.microsoft.com
for details.
DirectX 11.1 is built into Windows 8, Windows RT (the tablet-only version of Windows 8 for ARM
processors), and Windows Server 2012. Some of its improvements over DirectX 11 include:
• Improved 2D and 3D rendering
• Ability to discard resources and resource views and to clear unneeded resource views
• Shader Model 5.0 instructions are now usable in all shader stages
For more details about the differences between DirectX 11 and 11.1's DirectDraw features, see
It's important to realize that DirectX 10/11/11.1 GPUs retain full compatibility with DirectX 9.0c and
earlier DirectX versions, so you can play the latest games as well as old favorites with a DX10 or
DX11-compliant video card. Updates for DirectX are provided via
www.windowsupdate.com
.
More
