ATI's GPU for Xenon-Xbox2


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.
 
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X

Xenon

quick correction-

It seems that Xenon-Xbox2's GPU will be a preview of ATI's next-next
generation R600, rather than R520 which is built on R300 technology like the
R420 was.


where I wrote R500 in my original post, I meant to write R520.
 
S

sTuFf

where I wrote R500 in my original post, I meant to write R520.

Oh you naughty boy! You must be punished!
 
C

Cheddar

Xenon said:
quick correction-

It seems that Xenon-Xbox2's GPU will be a preview of ATI's
next-next
generation R600, rather than R520 which is built on R300
technology
like the R420 was.


where I wrote R500 in my original post, I meant to write
R520.

I wonder how this will compare to the latest PC gaphics
cards that will be around when the XBox 2 is released.

Does anyone have a roadmap for the next gen cards due out in
the next few years for the PC?
 
M

MS

Well, current PC games hardly use all features of GF4 generation
cards...that's one thing that makes consoles better for gaming - the games
actually use the features, and are optimized for the hardware.

On pc, developers don't really optimize their code, so when the code doesn't
run smoothly, the simply throw more memory, faster cpus and gpus at it until
it does.
 
T

Tom Brown

MS said:
On pc, developers don't really optimize their code, so when the code doesn't
run smoothly, the simply throw more memory, faster cpus and gpus at it until
it does.


In case you haven't noticed, the code isn't "optimized" for the consoles
either. They just use smaller textures and create very small levels.
Unfortunately, we in the PC world see that all too often in games designed
for both platforms at the same time... we get levels that are ridiculously
too small for a PC game (Deus Ex: Invisible War, for example), thanks to the
limits of the console version...
 
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M

msgs

-Sure, this is the case sometimes, but there isn't as good game as PGR2 for
PC. Not a single driving game for PC comes even close. And I enjoyed (and
still do) Halo more on XBox than on a more powerful pc.
 
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H

hg

In case you haven't noticed, the code isn't "optimized" for the consoles
msgs said:
-Sure, this is the case sometimes, but there isn't as good game as PGR2 for
PC. Not a single driving game for PC comes even close. And I enjoyed (and
still do) Halo more on XBox than on a more powerful pc.

That's coz the PC version was coded by buffoons. Anyway it's all pointless
talking about PC hardware Vs every other console's hardware at this moment
in time, coz the current console's can all be emulated by powerful enough
2004-5 PCs. All the emu's are coming along nicely and should all be playable
in 2005. What the real difference between PCs and consoles when it comes
down to it is the people who make the games. All the 'arcadey ' developers
are on the consoles hammering away at coding cool stuff, whereas PC gamers
only get to play a couple of outstanding true arcade games a year. A few
weeks ago somebody asked a question in one of the videocard groups asking
why most console games never get ported to the PC. A simple question that
was surprisingly hard to answer - a lot of good responses were given and I
don't want to repeat them, but I will point out something that was missed.
In the late nineties Sega converted a string of arcade games to the PC and
then they gave up on the PC, round about the time PC 3D accelerators started
getting some serious power rendering power. I guess just _one_ of the
reasons why they gave up was that the conversions - if coded properly -
would actually look better than the arcade games on which they were based.
Same is still true today, and I'm just thinking about what flawless arcade
eclipsing conversions of hits like Tekken 4, Virtua Fighter 4 could be
programmed on PC's equipped with the latest DX9 cards. But it ain't gonna
happen coz 1) The developers aren't on the PC to begin with 2) The business
model is not there to convert and enhance arcade games, rather a straight
port that'll save the bosses cash and 3) The public won't buy these arcade
games unless they are clearly superior to the console/arcade versions, which
is kinda a vicious circle back to the beginning IMHO.
 

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