It's certainly not the first time that we see a modder altering the GDDR6 DRAM amount on a graphics card, and there you have it, GeForce RTX 3070 modded to 16 GB GDDR6.

This Geforce RTX 3070is equipped with 8 GB as standard. That may be enough for most cases at the moment, but it is not totally future-proof and anyone who is in the enthusiast area would agree, 16 GB is better.  The SMT soldered Samsung modules type K4Z803256C-HC14 can be exchanged for modules of type K4ZAF3258M-HC14. They are almost identical with the subtle difference that the capacity is doubled from 1 Gbit to 2 Gbit. After a bit of fiddling with even the card recognized the new 16GB partition. Unfortunately, it really needs a BIOS mod with proper timings, voltages and frequency to become a proper success. And that last bit is getting more complicated. 

It didn't work 100%; software like 3D Mark, Furmark and Crypto mining ran without restrictions, but the card did not render 3D graphics problem free. Here and there it created generated black screens. Further tests showed it is clock frequency-related.