Pre-E3 2005: Xbox 360 The Hardware
Microsoft unveils its engine. We reveal the details, chips, numbers, theory
and everything else in between.
by Douglass C. Perry
May 12, 2005 - "Silicon," said Todd Homdahl, the designer of Microsoft's
custom chipset for the Xbox 360, "is the biggest lever in hardware." For a
company that's been through its first round as a console manufacturer in the
videogame industry and lost a lot of money on its first console, Homdahl's
words spoke volumes. The chief chip designer sat down with us early last
week at Microsoft, unveiling the chipsets, the architecture of the upcoming
Xbox 360, and the blueprints of the chips themselves.
"We want to design the most powerful, elegant and useful design for
developers to create games with Xbox 360," said the impressively tall, lanky
Holmdahl. "With the Xbox we had a merchant semi-conductor relationship. With
Xbox 360 we have designed and own the chipset, so we can go to whomever we
want with it. We're not paying Intel and Nvidia this time," he explained,
referring to the exorbitant price paid out each time an Xbox was
manufactured.
The heart of Microsoft's new system is the CPU, a triple core of 3.2 GB
processors, each capable of running two threads simultaneously, meaning the
CPU can generate six threads at once. This power enables, among other
things, programmers to give an immense amount of commands to the Central
Processing Unit without strain. It also provides programmers with the
ability to invent new algorithms in the future, giving them a healthy
flexibility in the way they code games. The CPU memory bandwidth is 5.4
gigabits or 5.4 GHz, 32 lines or 4 bytes, with 21.6 gigabytes per second on
the frontside bus connecting the CPU and the GPU.
The CPU is an amazing piece of technology, as it's built with 165 million
transistors in it, many the size of mere nanometers. IBM had three plants
working on the development of the chips.
The CPU is joined by the GPU, the Graphic Processing Unit, which handles the
graphic output of the system (and which has 150 million transistors in it),
the Southbridge, which enables all of the Ethernet and controller issues,
and the TV encoder, which handles resolution issues, such as progressive
scan, interlacing and other TV related issues.
The GPU has the ability to generate 48 shader units using an advanced shader
language. In the standard PC, you have both vertex shaders and pixel
shaders, each working individually. In the Xbox 360, the Shader units can do
either, meaning you can have scenes with only a little bit of geometry and a
tremendous number of effects, such as a fightng game with only two
characters on screen (like Dead Or Alive 4). Or you can deliver tons of
geometry with fewers effects, such as a a 100-person action online game
(such as Possession or Huxley). It has 512 MB of main memory with a 10MB
framebuffer. And it's got 10MB embedded DRAM.
In discussing the design of the chipsets, Holmdahl's very focused
conversation included elements we weren't aware even took part of console
design. "We worked with wind tunnel companies to decrease the noise and
sound of the system." All computers have fans or cooling systems to keep the
silicon from melting, and the Xbox uses a combination of both. It has a
built-in, air-tight coolant system that looks like a miniature water heater.
It sucks the hot air out of the core chip area and passes it through a
carefully engineered wind tunnel to exit it out of the system. Other
chipsets use miniature fans to keep the heat down. "This system will be
quieter than Xbox 1." Which is saying something, considering how loud the
PlayStation 2 is in comparison.
The full official spec list is as follows:
a.. An IBM PowerPC based CPU with 3 symmetrical cores running at 3.2 GHz
each, packing the most-advanced artificial intelligence and physics
processing available
b.. A custom ATI Graphics processor and more than 512 MB of memory for
high definition games and entertainment applications
c.. All games optimized for 16:9 aspect ratio, HD Output (720p and 1080i);
multichannel surround sound output
d.. Detachable and upgradeable 20GB hard drive to download demos and
trailers along with new game levels, maps, weapons, vehicles, skins,
community-created content, and more; to rip music for playback and to listen
to custom play lists in every game
e.. A wireless controller with Microsoft-patented wireless technology;
Xbox Guide Button on every controller, the launch pad that instantly
connects gamers to their games, friends, and music and to power on or power
off Xbox 360 without leaving the couch
f.. Gamer Profile software that remembers what players have achieved in
games
g.. Instant, out-of-the-box access to Xbox Live, including: a built-in
Ethernet port for connectivity; Xbox Live Marketplace for downloadable
content; a Message Center to receive voice and video messages from friends;
ability to talk to friends, even while watching movies or listening to
music; and an Xbox Live Headset
h.. 3 USB 2.0 ports for Xbox Live Camera peripheral; to plug in wired game
controllers that are also common for Windows PCs; to stream media from any
portable media device, digital camera, and Windows XP PC
i.. Progressive-scan DVD movie playback out of the box; DVD and CD music
and photo playback out of the box; support for DVD-Video, DVD-ROM, DVD-R/RW,
DVD+R/RW, CD-DA, CD-ROM, CD-R, CD-RW, WMA CD, MP3 CD, JPEG Photo CD
j.. Windows Media Center Extender built in to access recorded TV
(including high definition) and digital movies (including high definition),
music, video and photos stored on Windows XP Media Center Edition 2005-based
PCs through any Xbox 360
k.. Support for up to four wireless game controllers and an optional
Universal Media Remote with Windows® XP Media Center Edition Button for
Media Center Edition functionality
l.. Support for Xbox 360 Wireless Network Adapter via 802.11b, g and a
m.. Interactive, full screen 3D visualizers
n.. Two memory unit ports to save data on portable memory units, starting
at 64 MB
o.. Detachable Face so each console can be personalized
p.. Parental Controls to restrict the games and movies that are played;
Xbox Live controls to manage Friends List, voice and video communication,
and Gamer Profile sharing
