Xbox 2 innards laid bare on web

Microsoft’s Xbox 2 architecture has been exposed for all to see – if a posting on a Chinese bulletin board is to be believed.

The schematic, which appears here on, reveals a three-core 3.5GHz CPU backed by 256MB of main memory and a 500MHz graphics chip.

In what may be a blow to hopes of some AMD fans that the Xbox 2 contains Athlon 64 processor technology, the CPU is linked to main memory via a traditional North Bridge, not through an integrated memory controller.

According to the spec, each of the processor’s three cores contains its own vector processing unit, along with 64KB of L1 cache, split 50:50 between data and instructions. The three cores share a single on-die L2 cache that’s 1MB in size.

The processor connects to the North Bridge across a bi-directional bus with a total bandwidth of 21.6GBps, according to the spec. That, in turn links up to the South Bridge over a two-way 500MBps bus.

The console’s unnamed graphics chip – known to be coming from ATI – apparently contains 10MB of embedded DRAM within the packaging. The GPU itself can run through 16 pixel shader interpolations per cycle, the schematic claims, along with 16 bilinear texture fetches and 48 ALU ops in the same period. The vertex shader and pixel shader are load balanced.

News source:

The North Bridge also feeds through to the console’s video scaler unit.

The South Bridge features integrated DVD and 100Mbps Ethernet support, along with hard disk support, though the spec. notes that whether such a unit will be built into the console remains “not decided”.

GZeasy notes separately that Xbox 2 will be officially announced on 2 June, though whether that’s in preparation for a Christmas launch or a release in 2005 isn’t known – assuming the June date is accurate. ®


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