HBM2 is a collection of stacked DDR memories accessible in parallel to give a total bandwidth that is the aggregate of the total.
Figure 1: Stratix 10 with two HBM2 memories connected on the die
The Intel® Stratix® 10 MX device used on the Bittware 520N-MX card has two HBM2 memory stacks. Each memory stack supports up to 8 independent physical channels (or 16 independent pseudo channels), with each physical channel providing 8Gbit of capacity. This translates to 8GB of capacity for each HBM2 memory stack giving a total of 16GB of HBM2 memory in the Intel® Stratix® 10 MX device. On the -2 speed grade device, the maximum bandwidth from the HBM2 devices is 409 GBytes/sec. – a 5x improvement over previous FPGA cards.
Figure 2: Comparison of memory bandwidth for previous OpenCL enabled FPGA cards