QuoteConversely, fourteen 6 GB GDDR7 packages would yield exactly 84 GB and correspond to a 448-bit bus.
"6 GB GDDR7 packages" sounds like there are 6 GB per GDDR7 dense chips, but they don't exist, only 2 and 3 GB per GDDR7 chip memory densities exist. But a 448-bit wide memory interface looks correct:
84 GB VRAM = 14 GDDR7 chips, using 32-bit per chip * 3 GB per chip * 2, because chips are on both sides of the PCB (28 GDDR7 chips in total (and 28 chips * 3 GB per chip = 84 GB)), aka clamshell VRAM design.