Xenon (processor)

Microsoft XCPU
(codenamed Xenon)

Picture of the microprocessor (XCPU-ES shown).
General information
Designed by	IBM
Common manufacturer(s)	IBM, GlobalFoundries
Cache
L1 cache	32/32 KB
L2 cache	1 MB
Architecture and classification
Instruction set	PowerPC
Physical specifications
Cores	3 cores

Microsoft XCPU, codenamed Xenon, is a CPU used in the Xbox 360 game console, to be used with ATI's Xenos graphics chip.

The processor was developed by Microsoft and IBM under the IBM chip program codenamed "Waternoose", which was named after the Monsters, Inc. character Henry J. Waternoose III.^[1] The development program was originally announced on November 3, 2003.^[2]

The processor is based on IBM

• 45 nm process since Xbox 360 S model^[8]
• 165 million transistors
• Three cores, each two-way SMT-capable and clocked at 3.2 GHz^[6]
• SIMD: Two VMX128 units with a dedicated (128×128 bit) register file for each core,^[6]
  one for each thread
• 1 MB L2 cache^[6] (lockable by the GPU) running at half-speed (1.6 GHz) with a 256-bit bus
• 51.2 GB/s of L2 memory bandwidth (256 bit × 1600 MHz)
• 21.6 GB/s front-side bus (On the CPU side, this interfaces to a 1.35 GHz, 8B wide, FSB dataflow; on the GPU side, it connects to a 16B wide FSB dataflow running at 675 MHz.)^[6]
• Dot product performance: 9.6 billion per second
• In-order instruction execution^[6]
• 768 bits of
  IBM eFUSE-based OTP memory^[9]
• KB SRAM) storing Microsoft's Secure Bootloader, and encryption hypervisor^[9]
• Big-endian architecture

XCGPU

The

XCGPU contains 372 million transistors and is manufactured by GlobalFoundries on a 45 nm process. Compared to the original chipset in the Xbox 360 the combined power requirements are reduced by 60% and the physical chip area by 50%.^[10][11]

Gallery

Illustrations of the different generations of processors in Xbox 360 and Xbox 360 S.

• 
  The original XCPU-ES manufactured at 90 nm by IBM in 2005. ES stands for "Engineering Sample" and the device is packaged by IBM at their Bromont facility in Canada. It runs at 2.8GHz, as opposed to the final chip, which ran at 3.2GHz.
• 
  The 90nm XCPU manufactured at 90 nm by Chartered in Singapore 2006.
• 
  The 65nm XCPU manufactured at 65 nm by Chartered in Singapore 2007.
• 
  The two chips of the XCGPU: The larger is the XCGPU itself and the smaller is the 10 MB eDRAM. Manufactured at 45 nm by Global Foundries in Singapore in 2010.
• 
  The XCGPU with heatspreader. The complete device is packaged by IBM at their Bromont facility in Canada.

References

• Xenon hardware overview Archived February 20, 2006, at the Wayback Machine by Pete Isensee, Development Lead, Xbox Advanced Technology Group, written some time before June 23, 2007

External links

• Ars Technica explains the Xenon CPU