This is a good observation, the cards do have different memory bandwidth with the MI210 having more than double the bandwidth via HBM2e.
Note that the comparisons between the two cards (MI210 and A6000) are being made for high throughput workloads, and in this regime the performance is compute bound. So as long as the memory bandwidth is decent (as it is for GDDR6 with 768.0 GB/s) the lower memory bandwidth is not the main bottleneck. There are also other architectural differences so any comparison will ultimately be imperfect, but we found A6000 to be the closest match for the workloads that we cared about (ie high throughput workloads at reasonable latencies).
Also worth noting that there are still more stack optimizations on the table, which again can shift the bottleneck between compute and memory. In those cases it might makes sense to compare with another card with matched memory bandwidth.
Note that the comparisons between the two cards (MI210 and A6000) are being made for high throughput workloads, and in this regime the performance is compute bound. So as long as the memory bandwidth is decent (as it is for GDDR6 with 768.0 GB/s) the lower memory bandwidth is not the main bottleneck. There are also other architectural differences so any comparison will ultimately be imperfect, but we found A6000 to be the closest match for the workloads that we cared about (ie high throughput workloads at reasonable latencies).
Also worth noting that there are still more stack optimizations on the table, which again can shift the bottleneck between compute and memory. In those cases it might makes sense to compare with another card with matched memory bandwidth.
paul @ mk1