>The big news to me is that the top card features a 320 bit memory bus, which should offer much better memory bandwidth than the previous generation (256 bits).

RTX 2080 is 352 bits, and RTX Titan is 384. Nvidia has always had high bit rate memory bus. The one that had 256 bit was AMD Radeon GDDR. Arguably bit bandwidth is meaningless without looking at actual memory type, or the total bandwidth from memory.