AMD develops fast and economical hbm video memory

The American technology company AMD has developed a method to overcome the memory bottleneck for video cards. The so-called high bandwidth memory must not only be faster, but also more economical than current memory structures.

The high-bandwidth memory technology, or hbm for short, developed by AMD, would be especially suitable for video cards, but in the long run, accelerated processing units, or APUs, could also be equipped with the memory technology. AMD’s hbm technology should satisfy graphics processors’ hunger for memory bandwidth; video cards are using more and faster memory to render high resolutions and details on the screen. A simple solution for this is an ever wider memory bus. However, this not only requires more and more physical memory chips and therefore a large surface area on the pcb, but also increasingly heavier power supplies on the cards and increasing costs.

With the hbm technology, the memory chips are placed much closer to the processor, allowing wider data buses. A first version of the technique would allow a memory bus of thousands of bits, where conventional buses peak at 512bit. An interposer is used to place the memory chips so close to the graphics processor. This is a kind of printed circuit board on which the processor and the memory are attached and through which very short connections between the memory and the processor run. In order to save even more space and enable higher speeds, the memory is also stacked, a technique that is used in hybrid memory cubes, among other things. AMD builds memory towers of four chips high, which are linked to each other via TSVs. With four dies per stack and four stacks around the processor, the maximum memory is currently 4GB. In the future, that should increase thanks to eight or sixteen layers.

Despite the much wider memory data bus, the bandwidth of first version HBM memory constructs is not much greater than existing memory architectures. This is because the clock speed of the memory is much lower, which in turn benefits the heat production. AMD would soon come up with products that incorporate the HBM technology. Whether that will be completely new video cards or new versions of existing models is not yet known. However, hbm video cards could be more economical, and allow smaller pcb’s and thus more compact cards.