Xbox 360 System Bandwidth and Memory

The Xbox 360 features 512 MiB of 700 MHz GDDR3 RAM on a 128-bit bus. This memory is produced by either Qimonda or Samsung and is shared by the GPU and the CPU via the unified memory architecture.

The console has a large amount of bandwidth in comparison to the Sony PLAYSTATION 3 (278.4 GB/s compared to just 48 GB/s); however this figure includes the eDram logic to memory bandwidth, and not internal CPU bandwidths. The high bandwidth is used primarily for alpha blending, z-buffering and antialiasing, saving time and space on the GPU die. Between the GPU and the eDram die, data is transferred at 32 GB/s. The memory interface bus has a bandwidth of 22.40 GB/s and the southbridge a bandwidth of 1 GB/s.