While not at all an Apple product, the Xbox 360 shares some strikingly close DNA to Apple computers of the mid-2000s. Namely, the IBM PowerPC chip which powers the Xbox at its core. This chip was announced on July 7th, 2005 in Tokyo, at the Power Everywhere forum, alongside the third-generation G5 chip, the 970MP. This article compares and contrasts the original Xbox 360 chip with the very last PowerPC Mac CPU from 2005.

Just like the second-gen 970fx and the third-gen 970MP, the Xbox 360 CPU has a 90 nanometer fabrication size. There are major internal differences between the XCPU and the PowerPC G5 chips, as the XCPU is meant more for gaming while the G5 is more for computing.

• See: Power旋風が吹いたマルチコアプロセッサ (Translation: Multi-core processor with a whirlwind of Power)

The XCPU came with 32 KB instruction cache and 32 KB data cache – just like the G3s and G4s. Unlike all the G5s which come with 64 KB instruction cache, the Xbox 360 has half.
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Xenon XCPU “Loki” Key Features and Notes

This CPU is notable for being a Tri-Core processor, having 3 cores. On this Xenon, there’s 1 MB of shared L2, 165 Million transistors, and it’s clocked at 3.2 Ghz.

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Some key contrasts between the 970MP and the Xenon

Note: On a Mac, the System Profiler will read each core as a CPU with its own separate L2 cache. The total amount of L2 cache will still be counted the same way for a total of 4 MB. In this article, the 970MP is referred to as a Dual-Core chip, so the “2MB Per-CPU” refers to 1 whole chip.

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Xenon layout diagrams

Cell Broadband Engine – Diagram 1

Cell Broadband Engine – Diagram 2

Package Design