Microsoft XCPU, codenamedXenon, is aCPU used in theXbox 360 game console, to be used withATI'sXenos graphics chip.
The processor was developed byMicrosoft andIBM under the IBM chip program codenamed "Waternoose", which was named after theMonsters, Inc. characterHenry J. Waternoose III.[1] The development program was originally announced on November 3, 2003.[2]
The processor is based on IBMPowerPCinstruction set architecture. It consists of three independentprocessor cores on a single die. These cores are slightly modified versions of thePPE in theCell processor used on thePlayStation 3.[3][4] Each core has two symmetric hardware threads (SMT), for a total of six hardware threads available to games. Each individual core also includes 32 KB ofL1 instruction cache and 32 KB of L1 data cache.
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/sfront-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]
TheXbox 360 S introduced theXCGPU (codename Vejle), which integrated the Xenon CPU and theXenos GPU onto the same die, and theeDRAM into the same package. The XCGPU follows the trend started with the integrated EE+GS inPlayStation 2 Slimline, combining CPU, GPU, memory controllers and IO in a single cost-reduced chip. It also contains a "front side bus replacement block" that connects the CPU and GPU internally in exactly the same manner as thefront side bus would have done when the CPU and GPU were separate chips, so that the XCGPU doesn't change the hardware characteristics of the Xbox 360.
XCGPU contains 372 million transistors and is manufactured byGlobalFoundries on a 45 nm process. Compared to the originalchipset in the Xbox 360 the combined power requirements are reduced by 60% and the physical chip area by 50%.[10][11]
In 2014, the Winchester Xbox 360 system introduced a shrunken XCGPU on a 32 nm process (codename Oban). This chip is no longer a multi-chip-module and integrates the eDRAM into the main die.
Illustrations of the different generations of processors in Xbox 360 and Xbox 360 S.
The original XCPU DD2 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 DD3 manufactured at 90 nm by Chartered in Singapore 2006
The 65nm XCPU "Loki" manufactured at 65 nm by Chartered in Singapore 2007
The two chips of the XCGPU "Vejle": 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.
