In this video from the 2015 Hot Chips Conference, Joe Macri from AMD presents: AMD’s next Generation GPU and High Bandwidth Memory Architecture.
“HBM is a new type of CPU/GPU memory (“RAM”) that vertically stacks memory chips, like floors in a skyscraper. In doing so, it shortens your information commute. Those towers connect to the CPU or GPU through an ultra-fast interconnect called the “interposer.” Several stacks of HBM are plugged into the interposer alongside a CPU or GPU, and that assembled module connects to a circuit board. Though these HBM stacks are not physically integrated with the CPU or GPU, they are so closely and quickly connected via the interposer that HBM’s characteristics are nearly indistinguishable from on-chip integrated RAM.”
Beyond performance and power efficiency, HBM is also revolutionary in its ability to save space on a product. As gamers increasingly expect smaller and more powerful PCs, the elimination of bulky GDDR5 chips in favor of HBM can enable devices with exciting new form factors that pack a punch in a smaller size. Compared to GDDR5, HBM can fit the same amount of memory in 94% less space.