Is the latency comparable between high end DDR4 (say DDR4 4200) and GDDR6? If not how much of a difference is there? Does GDDR6 still use burst memory reads (where it reads 4 sets of 8 bytes I think)?
The question is whether there is a tool which can report CAS latency (at least) for a GDDR chip. If yes, you take the frequency and calculate time, of course there are different factors which affect real latency.
GDDRs are in general optimized for extremely high read and wite rates (wide bus, high frequency etc).