XCPU
The Microsoft XCPU, codenamed Xenon, is the central processor used in the Xbox 360 game console. It is designed to be used with the ATi Xenos graphics chip, which also functions as the northbridge and memory controller.
The processor was developed by Microsoft and IBM, and the first version was codenamed Waternoose after the fictional character Henry J. Waternoose III.
Specifications
- 3 two-way SMD-capable RISC cores clocked at 3.2GHz
- SIMD: Two VMX128 units
- 32KB L1 data cache
- 32KB L1 instruction cache
- 1MB L2 cache at 1.6 GHz with a 256-bit bus
- 21.6GB/s FSB
- 768 bits of IBM eFUSE one-time-program memory
- ROM and 64KB SRAM for storing the 1BL
- Big-endian architecture
Versions
Multiple versions of the XCPU have been created for different motherboard types
90nm
The initial version of the XCPU, codename Waternooose, entered production in 2005 and is used on the Xenon and Zephyr motherboards. It is notable for running hot and being power hungry.
65nm
In 2007, XCPU was shrunk and slightly redesigned for the 65nm process. Codename Loki, it is used on the Falcon and Jasper motherboards. It is notable for running cool and having a significantly lower TDP.
45nm (CGPU)
In 2010, the XCPU was shrunk to the 45nm process and combined with the Xenos graphics chip to create a system-on-a-chip, called the XCGPU. The eDRAM remains on a separate die, and an IHS was added. Codename Valhalla, it is used on the Trinity and Corona motherboards.
Winchester
In 2014, the XCGPU process was shrunk by an unknown amount and the eDRAM die was integrated into the CGPU die. The codename and specifics for this chip are unknown. The single die design meant that the IHS was no longer needed. It is used on the Winchester motherboard and is notable for patching the RGH exploit.