Eviscerating the Xbox 360 Elite

In late April, Microsoft refreshed its nearly 1.5 year old Xbox 360 product line with the high-end Elite variant, touting an upgraded-capacity 120Gbyte HDD and an HDMI v1.2 digital audio-and-video interface. When you crack open the Elite's sleek black case, what - if any - alterations to the initial console design will you discover, beyond the HDMI augmentation?


Four of the Xbox 360 ICs carry Microsoft labels. In contrast to the first-generation Xbox, for which Microsoft depended on the supply-versus-demand whims of its IC partners, the company this time acquired IP from other companies and directly manages chip manufacturing. The system's south bridge IC contains circuits from SiS; this chip's functions include SATA controllers for the system HDD and DVD drive, USB2 transceivers, audio DACs, and the Ethernet MAC.

The Ethernet PHY comes from ICS; Broadcom is an alternate source. A transceiver and antenna residing on a separate daughterboard (not shown) handle the 2.4GHz wireless communication between the console and its game controllers.

The bulk of system memory takes the form of 512Mbytes of GDDR3 SDRAM. Four of the 512Mbit ICs (multisourced from Qimonda and Samsung) locate on the PCB topside; the other four are mirror-image mounted on the motherboard backside. Because the Xbox 360 comes in an HDD-less Core variant, a Hynix 128Mbit NAND Flash memory serves as an alternate storage location for operating-system patches and other code and data updates. Some versions of the motherboard (not shown) also include a 2kbit Atmel EEPROM directly below the CPU.

The Xbox 360's hardware scaler represents the single biggest evolution in the system design transition from the Core and Premium Xbox 360 models to the Elite version. This scaler is also a notable differentiation from the hardware-scaler-deficient Sony PlayStation 3. Microsoft uses the scaler to increase and decrease the resolution of, as to interlace and de-interlace, game and video content to match the connected display's desired attributes. The Core and Premium systems’ Ana scaler IC embeds the necessary DACs for various analog video connections; the Elite’s Hana" scaler (H=HDMI?) presumably also integrates the HDMI transmitter and therefore has access to both the digital-video and -audio data coming from other system ICs. Missing from the Elite motherboard is a Cypress clock generator IC that was just to the left of Ana; a migration from TQFP to BGA packaging for the scaler IC also marks the Ana-toHana-transition.

Under the heat sink, the GPU is a multidie module comprising the graphics processor and a separate 10Mbyte frame buffer memory IC. Analysis by Semiconductor Insights suggests that neither the CPU nor GPU has yet migrated from a 90-to-65-nm lithography; single-IC GPU integration is one possible outcome of the 65-nm conversion slated for later this year.

The Xbox 360 has no discrete boot memory IC; Microsoft learned a lesson from the hacker community on first generation Xbox, whose exposed traces between the CPU and flash memory were its Achilles’ heel. This time Microsoft embedded the system firmware within the CPU. The boot code is in-system-upgradable.



Click here for Illustrations:

Figure 1