Xenon (processor)

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Xenon is a CPU that is used in the Xbox 360 game console.^[1] The processor, codenamed "Waternoose" by IBM^[2] and "XCPU" by Microsoft is based on IBM's PowerPC technology, consisting of 3 independent cores on a single chip. Each of the cores has two symmetric hardware threads (SMT), for a total of six hardware threads available to games. Each individual core also includes 32 KiB of L1 instruction cache and 32 KiB of L1 data cache.

The processors are labelled "XCPU" on the packaging and are manufactured by Chartered. Chartered will reduce the fabrication process in 2007 to 65 nm, thus reducing manufacturing costs for Microsoft.

The Name "Xenon" comes from the original idea of the name for the next-generation Xbox, being "Xenon". They then proceeded to choose the name "Xbox 360" for the next-gen Xbox.

[edit] Specifications

• 90 nm process, alleged 65 nm process upgrade in 2007 (codenamed "Zephyr"), 165 million transistors
• Three symmetrical cores, each two way SMT-capable and clocked at 3.2 GHz
• SIMD: VMX128 (similar to AltiVec, just with more registers)
• 2× (128×128 bit) register file for each VMX128 unit, 6 in total.
• 1 MiB L2 cache (lockable by the GPU) running at half-speed (1.6 GHz) with a 256-bit bus
• 51.2 gigabytes per second of L4 memory bandwidth (256 bit × 1600 MHz)
• 21.6 GB/s Front-Side Bus
• DOT products performance: 9.6 billion per second
• 116 GFLOPS theoretical peak performance
• Restricted to In-order code execution
• ROM storing Microsoft's Secure Bootloader
• Big endian architecture.

[edit] References

1. ^ IBM press release: IBM delivers Power-based chip for Microsoft Xbox 360 worldwide launch, San Jose, CA, 25 October 2005
2. ^ "Learning from failure - The inside story on how IBM out-foxed Intel with the Xbox 360", Dean Takahashi, Electronic Business, May 1, 2006

• Xenon hardware overview by Pete Isensee, Development Lead, Xbox Advanced Technology Group, written some time before 23 June 2004
• IBM developer conference: Application-customized CPU design paper, 6 December 2005

[edit] External links

• IBM Developerworks - Xenon processor reference
• Ars Technica explains the Xenon CPU