What’s Inside the Microsoft XBOX 360

Electronic Products magazine publishes a column that describes the component content of popular electronic products.  In the January 2006 issue, the XBOX 360 was profiled.  All information in this blog entry is taken from [1] and information for the Electronic Products article was provided by iSuppli Corporation.

Architecture

The XBOX 360 has an IBM Power PC based CPU with 3 cores each running at 3.2 GHz.  It has 512 Mbytes of SDRAM.  The SDRAM is contained in 8 chips soldered on board, each chip being a 16M x 32 bit.  It would be interesting to know how the memory is organized, such as how many banks, how many memory controllers, is interleaving used, etc.  The memory is running at 700 MHz DDR for a total data rate of 1.4 Gbps per data pin.  I have not used this type of memory before, and it is a Samsung Graphics DDR SDRAM part (K4J52324QC-BC14).  According to Microsoft’s web site, the memory bandwidth is 22.4 GB/s which means that at 1.4 Gbps per pin, only 128 data pins are accessible at a time.  That probably means the memory architecture is not interleaved, since with 8 x32 chips there are 256 data pins available.  The front side bus data bandwidth is specified at 21.6 GB/s.

This design architecture is screaming fast, and based on the speed I would guess takes a lot of power!  I have read several sources on the internet that put the power consumption at 160 W.  They probably had a lot of design headaches trying to get all the heat out.

The motherboard dimensions are 10.5″ x 8.25″, and it is a 4 layer board.

The power density on the motherboard at 160 W is 1.85 W / sq. in.  For comparison, I thought a design I worked on that had a power density of 0.55 W / sq. in. was very difficult.  There must be some pretty exotic cooling mechanisms in the Xbox 360 to dissipate this much heat.  If anyone knows anything about the thermal design of the Xbox, please post.

Cost Content by function

The component content cost by function was reported to be:

CPU – 22.8%
GPU – 30.0%
Storage Device – 15.7%
Memory – 14.6%
Mechanical / Electromechanical – 7.7%
Power Supply – 2.9%
Southbridge – 2.5%
Display Driver – 2.0%
Interface – 1.6%
Clock – 0.3%

Cost Content by Part Family

Integrated Circuit – 65.8%
Storage Device – 14.1%
Accessories – 10.2%
Mechanical – 4.5%
Electromechanical – 2.5%
Passive – 2.0%
Discrete Semiconductor – 0.9%
Optical Semiconductor – 0.1%

[1] “What’s Inside? Microsoft Xbox 360.” January 2006. Electronic Products pp 56-59.