X
Xenon
an unofficial description of ATI's graphics architecture for Xenon aka Xbox2
quote:
"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.
As with Xbox, Xenon will support precompiled push buffers ("command buffers"
in Xenon terminology), but to a much greater extent than the Xbox console
does. The Xbox team is exposing and documenting the command buffer format so
that games are able to harness the GPU much more effectively.
In addition to an extremely powerful GPU, Xenon also includes a very
high-quality resize filter. This filter allows consumers to choose whatever
output mode they desire. Xenon automatically scales the game's output buffer
to the consumer-chosen resolution."
http://www.xbox-scene.com/xbox1data/sep/EplZAyukEVDWcUicJE.php
It seems that Xenon-Xbox2's GPU will be a preview of ATI's next-next
generation R600, rather than R500 which is built on R300 technology like the
R420 was.
according to the above, Xenon-Xbox2 will go beyond DX9's Shader Model 3.0
but not all the way to Direct X Next / DX10's Shader Model 4.0 - one of
the cool things is, the on-chip graphics memory. this is one area that the
Playstation2 and Gamecube both have the advantage over the current Xbox.
uber fast graphics bandwidth. it allows things to be done that would choke
the Xbox's 6.4 GB/sec bandwidth. I'm glad Microsoft & ATI have seemingly
decided to correct this major flaw in the current Box.
not much longer until everything is revealed. between CES and GDC we should
have all or most of the Xenon-Xbox2 details.
quote:
"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.
As with Xbox, Xenon will support precompiled push buffers ("command buffers"
in Xenon terminology), but to a much greater extent than the Xbox console
does. The Xbox team is exposing and documenting the command buffer format so
that games are able to harness the GPU much more effectively.
In addition to an extremely powerful GPU, Xenon also includes a very
high-quality resize filter. This filter allows consumers to choose whatever
output mode they desire. Xenon automatically scales the game's output buffer
to the consumer-chosen resolution."
http://www.xbox-scene.com/xbox1data/sep/EplZAyukEVDWcUicJE.php
It seems that Xenon-Xbox2's GPU will be a preview of ATI's next-next
generation R600, rather than R500 which is built on R300 technology like the
R420 was.
according to the above, Xenon-Xbox2 will go beyond DX9's Shader Model 3.0
but not all the way to Direct X Next / DX10's Shader Model 4.0 - one of
the cool things is, the on-chip graphics memory. this is one area that the
Playstation2 and Gamecube both have the advantage over the current Xbox.
uber fast graphics bandwidth. it allows things to be done that would choke
the Xbox's 6.4 GB/sec bandwidth. I'm glad Microsoft & ATI have seemingly
decided to correct this major flaw in the current Box.
not much longer until everything is revealed. between CES and GDC we should
have all or most of the Xenon-Xbox2 details.