Central processing unit
The Xbox 360 takes a new approach to hardware compared to its predecessor. The CPU, named Xenon at Microsoft and "Waternoose" at IBM, is a custom triple-core PowerPC-based design by IBM. The CPU emphasizes high floating point performance through multiple FPU and SIMD vector processing units in each core. It has a theoretical peak performance of 115.2 gigaflops and is capable of 9.6 billion dot products per second. Each core of the CPU is simultaneous multithreading capable and clocked at 3.2 gigahertz. However, to reduce CPU die size, complexity, cost, and power demands, the processor uses in-order execution in contrast to the Intel Coppermine128-based Mobile Celeron used in Xbox which used more advanced out-of-order execution. The original chip uses a 90 nanometer process, although a 65 nanometer process SOI revision was originally planned for early 2007, but it has been delayed until mid-2007. A 21.6 GB/s front side bus, aggregated 10.8 GB/s upstream and downstream, connects Xenon with the graphics processor/northbridge. Xenon is equipped with a 1 MB Level 2 cache on-die running at half CPU clock speed. This cache is shared amongst the three CPU cores. The CPU also contains ROM storing Microsoft private encrypted keys, used to decrypt game data. The heat sink implemented to cool the CPU is composed of aluminum fins with copper base heat pipes. The heat sink is cooled by two 60 millimeter fans at the back of the console.
Graphics processing unit
While the first Xbox's graphics processing unit was produced by NVIDIA, the Xbox 360 uses a chip designed by ATI called Xenos. The chip was developed under the name "C1" and "R500" was often used to refer to it. The GPU package contains two separate silicon dies, each on a 90 nm chip with a clock speed of 500 MHz; the GPU proper, manufactured by TSMC and a 10 MB eDRAM daughter-die, manufactured by NEC. Thanks to the daughter die, the Xenos can do 4x FSAA, z-buffering, and alpha blending with no appreciable performance penalty on the GPU. The GPU also houses additional capabilities typically separated into a motherboard chipset in PC systems, effectively replacing the northbridge chip. An aluminum heat sink was implemented to cool the GPU in systems manufactured prior to the second half of 2007; after this time, the GPU heatsink was revised in order to better move heat away from the GPU die. The new heatsink is made from a different material and is connected to a new secondary heatsink (located in front of the CPU heatsink, to the right of the DVD drive) via a copper heatpipe.
Memory and system bandwidth
The console features 512 MB of GDDR3 RAM clocked at 700 megahertz with an effective transmission rate of 1.4 GHz on a 128-bit bus. The memory is shared by the CPU and the GPU via the unified memory architecture. This memory is produced by either Samsung or Qimonda.
The Xbox 360 has an extensive amount of bandwidth in comparison to its competition; however this statistic includes the eDram logic to memory bandwidth, and not internal CPU bandwidths. The eDram internal logic to its internal memory bandwidth is 256 GB/s. The high bandwidth is used primarily for z-buffering, alpha blending, and antialiasing; it saves time and space on the GPU die. Between the eDram die and the GPU, data is transferred at 32 GB/s. The memory interface bus has a bandwidth of 22.40 GB/s and the southbridge a bandwidth of 1 GB/s.
Audio and video
All games made for the Xbox 360 are required to support at least 5.1-channel Dolby Digital surround sound. The console works with over 256 audio channels and 320 independent decompression channels using 32-bit processing for audio, with support for 48 kHz 16-bit sound. Sound files for games are encoded using Microsoft's XMA audio format. An MPEG-2 decoder is included for DVD video playback. VC-1 or WMV is used for streaming video and other video is compressed using VC-1 at non-HD NTSC and PAL resolutions or WMV HD. The Xbox 360 also supports H.263 and H.264 MPEG-4 videos. Unlike the original Xbox, voice communication is handled by the console, not by the game code, allowing for cross-game communication. There is no voice echo to game players on the same console; voice only goes to remote consoles.
There are no digital video outputs such as DVI or HDMI on Core packages or Premium packages manufactured before July 2007; instead, HD-quality output can only be produced over VGA or component video. An HDMI port and cables is included in the Elite SKU. A wide array of SDTV and HDTV resolutions are supported by the console hardware; up to 1080p after the October 2006 software upgrade. While most games are rendered natively at 720p, the video from all games can be scaled by the hardware to whatever resolution the user has set in the console's settings; from 480i NTSC and 576i PAL all the way to 1080p HDTV. Up to 1080p, the resolution the console will output is only limited by the chosen display equipment's capability (TV, projector, etc.) and the video cables used to connect the two.
Storage
Early production runs of the Xbox 360 are equipped with a 12x DVD drive, capable of a maximum read rate of 15.9 MB/s. The original production DVD drives were manufactured by both LG and Toshiba. Beginning in November 2006, a new model the BenQ VAD6038 was introduced, which is said to run faster than the previous models and, in addition, is much quieter. Games are stored on standard dual-layer DVD-ROMs with 7 GB of usable space available for game content. The option to apply a regional lockout to games is available to publishers, although DVD region codes are always enforced for movies. Microsoft has implemented methods to prevent hacking through the drive. Later drive models have the external debug triggering removed and black hard glue added to cover all the chip and controller pins. The drive is able to read both DVD±R and DVD±RW in addition to being able to play DVD-Video out of the box, unlike its predecessor, which required the purchase of an add-on remote. The system is also capable of playing standard CDs along with CD-R/RW, CD-DA, CD-ROM XA, CD-Extra, WMA-CD, MP3-CD, and JPEG Photo CD.[15] Some users reported problems with the disc drive, as when a user changes the console's orientation, the inserted disc may brush against the drive's pickup assembly and incur scratches to it. The users manual advises against changing the consoles position while there is a disc in the drive. Announced at CES 2006 and first publicly shown at E3 2006, an external HD DVD drive was released in North America on November 7, 2006, for US$199.99, and in Japan on November 17, 2006, for ¥19,800. In Europe, the HD DVD drive will be released for €199.99/£129.99 in the UK, France, and Germany. For a limited time, the HD DVD drive will be bundled with an Xbox 360 Universal Media Remote, as well as an HD DVD copy of Peter Jackson’s King Kong. The drive will play HD DVD movies, although all Xbox 360 games will remain on the DVD format. Microsoft has no plans to include an internal HD DVD player in future Xbox 360 designs. The external drive connects to the Xbox 360 via USB and contains two integrated USB ports on the rear.
The Premium configuration of the system comes with a detachable 20 GB hard drive and it is optional to separately purchase one for the Core. It is not required for standard games. The 2.5" hard drive is connected through a SATA interface and spins at 5400 rpm. A new version of the Xbox 360 (The Xbox 360 Elite) has been announced along with a new 120 GB HDD. The 120 GB drive is packaged in a black case to match the Elite, unlike 20 GB drives which are grey, matching the top of the Core and Premium units. The 120 GB HDD retail price is US$179.99.
