Can they just slap more memory chips on a 3080 PCB? I would think they have to design and fab the chips with the wider bus.
Miners are really going to love the increased bandwidth if this rumor is true.
The 3080 PCB has two spots free for additional RAM chips so assuming they use a cut-down 3090 die it shouldn't be too much work I image. I'm not an EE though so who knows.
This is a picture of the FE PCB but all of the AIB boards had the same spots free: