I know this is a terrible question. I am trying to figure out what a friend asked me. We were talking about mining ETH and he said:
Back in 2016 2GB cards "stopped working" and that means that if the same thing happens again 8GB cards might be necessary
What could that mean? Was there a difficulty adjustment in 2016 that made a certain class of GPU cards obsolete for mining ETH? Was it part of ice age?
see here
The issue is to do with the DAG file size, which is loaded onto GPU memory in order for the ethash algorithm to call pieces of it during the hashing process. The DAG file grows with time, so as it gets bigger graphics cards will become obsolete if they can't hold the full file in their memory.
While this seems like a pain, this memory-intensive process helps keep Ethereum ASIC-resistant and thus GPUs remain a viable option for Ethereum mining (e.g. vs. Bitcoin, where ASIC miners dominate and the mining efforts of GPUs pale in significance)
