R
R420
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The Xenon GPU is a custom 500+ MHz graphics processor from ATI. The
shader core has 48 Arithmetic Logic Units (ALUs) that can execute 64
simultaneous threads on groups of 64 vertices or pixels. ALUs are
automatically and dynamically assigned to either pixel or vertex
processing depending on load. The ALUs can each perform one vector and
one scalar operation per clock cycle, for a total of 96 shader
operations per clock cycle. Texture loads can be done in parallel to
ALU operations. At peak performance, the GPU can issue 48 billion
shader operations per second.
The GPU has a peak pixel fill rate of 4+ gigapixels/sec (16
gigasamples/sec with 4× antialiasing). The peak vertex rate is 500+
million vertices/sec. The peak triangle rate is 500+ million
triangles/sec. The interesting point about all of these values is that
they're not just theoretical—they are attainable with nontrivial
shaders.
Xenon is designed for high-definition output. Included directly on the
GPU die is 10+ MB of fast embedded dynamic RAM (EDRAM). A 720p frame
buffer fits very nicely here. Larger frame buffers are also possible
because of hardware-accelerated partitioning and predicated rendering
that has little cost other than additional vertex processing. Along
with the extremely fast EDRAM, the GPU also includes hardware
instructions for alpha blending, z-test, and antialiasing.
The Xenon graphics architecture is a unique design that implements a
superset of Direct3D version 9.0. It includes a number of important
extensions, including additional compressed texture formats and a
flexible tessellation engine. Xenon not only supports high-level
shading language (HLSL) model 3.0 for vertex and pixel shaders but
also includes advanced shader features well beyond model 3.0. For
instance, shaders use 32-bit IEEE floating-point math throughout.
Vertex shaders can fetch from textures, and pixel shaders can fetch
from vertex streams. Xenon shaders also have the unique ability to
directly access main memory, allowing techniques that have never
before been possible.
_______________________________________________________________________________
can be found at the following links:
http://www.rage3d.com
http://forums.xbox-scene.com/index.php?showtopic=231928
http://www.beyond3d.com/forum/viewtopic.php?t=13470
I don't know what to make of this. While in some ways, the Xbox 2 GPU
is way ahead of the current Radeon X800 XT. like having 48 ALUs. I
think the X800 XT has only 22 (16 pixel pipes + 6 vertex shaders). As
well as Xbox 2 GPU on-chip eDRAM for framebuffer and z-buffer. plus
Shader Model 3.0++. no available ATI PC GPU has that stuff, yet. but
in other areas, the Xbox 2 GPU seems to be less than the Radeon X800
XT.
in fillrate:
X800 XT - 6.4 gigapixels/sec
Xbox 2 GPU - 4+ gigapixels/sec
in vertex/geometry performance:
X800 - 600 million vertices/sec
Xbox 2 GPU - 500 million vertices/sec
Obviously the Xbox 2 GPU specs are suspect. they're unconfirmed. could
be old or even completely fake. but assuming they are true, it gives
you something to chew on.
The Xenon GPU is a custom 500+ MHz graphics processor from ATI. The
shader core has 48 Arithmetic Logic Units (ALUs) that can execute 64
simultaneous threads on groups of 64 vertices or pixels. ALUs are
automatically and dynamically assigned to either pixel or vertex
processing depending on load. The ALUs can each perform one vector and
one scalar operation per clock cycle, for a total of 96 shader
operations per clock cycle. Texture loads can be done in parallel to
ALU operations. At peak performance, the GPU can issue 48 billion
shader operations per second.
The GPU has a peak pixel fill rate of 4+ gigapixels/sec (16
gigasamples/sec with 4× antialiasing). The peak vertex rate is 500+
million vertices/sec. The peak triangle rate is 500+ million
triangles/sec. The interesting point about all of these values is that
they're not just theoretical—they are attainable with nontrivial
shaders.
Xenon is designed for high-definition output. Included directly on the
GPU die is 10+ MB of fast embedded dynamic RAM (EDRAM). A 720p frame
buffer fits very nicely here. Larger frame buffers are also possible
because of hardware-accelerated partitioning and predicated rendering
that has little cost other than additional vertex processing. Along
with the extremely fast EDRAM, the GPU also includes hardware
instructions for alpha blending, z-test, and antialiasing.
The Xenon graphics architecture is a unique design that implements a
superset of Direct3D version 9.0. It includes a number of important
extensions, including additional compressed texture formats and a
flexible tessellation engine. Xenon not only supports high-level
shading language (HLSL) model 3.0 for vertex and pixel shaders but
also includes advanced shader features well beyond model 3.0. For
instance, shaders use 32-bit IEEE floating-point math throughout.
Vertex shaders can fetch from textures, and pixel shaders can fetch
from vertex streams. Xenon shaders also have the unique ability to
directly access main memory, allowing techniques that have never
before been possible.
_______________________________________________________________________________
can be found at the following links:
http://www.rage3d.com
http://forums.xbox-scene.com/index.php?showtopic=231928
http://www.beyond3d.com/forum/viewtopic.php?t=13470
I don't know what to make of this. While in some ways, the Xbox 2 GPU
is way ahead of the current Radeon X800 XT. like having 48 ALUs. I
think the X800 XT has only 22 (16 pixel pipes + 6 vertex shaders). As
well as Xbox 2 GPU on-chip eDRAM for framebuffer and z-buffer. plus
Shader Model 3.0++. no available ATI PC GPU has that stuff, yet. but
in other areas, the Xbox 2 GPU seems to be less than the Radeon X800
XT.
in fillrate:
X800 XT - 6.4 gigapixels/sec
Xbox 2 GPU - 4+ gigapixels/sec
in vertex/geometry performance:
X800 - 600 million vertices/sec
Xbox 2 GPU - 500 million vertices/sec
Obviously the Xbox 2 GPU specs are suspect. they're unconfirmed. could
be old or even completely fake. but assuming they are true, it gives
you something to chew on.
