Radeon RX 580 8GB vs 4GB. Does memory matter?

Question

Does GPU with more memory provide better mining for Ethereum? Here is a Quora an answer:

In general, 4GB is sufficient for even the most demanding hashing algorithms and you will not see any performance gains just by having more memory. This is where the speed and quality of the memory comes into play. The 8GB RX 480 has a higher memory clock speed which gives it a slight edge while running memory intensive algorithms such as Ethash (used by Ethereum). When running at the same core clock, the hashing speed of a 8GB RX 480 can be higher by 25–30 hash/sec compared to the 4GB RX 480.

However, hashing speed also depends on the quality of the GDDR5 memory. Samsung based chips seem to perform little better (20–25 hash/sec) compared to Hynix or Elpida. They are also easier to overclock.

What about Radeon RX 580, which one is better? In what cases should I consider memory?

Answer 1

Memory size does not affect mining speed.

To mine you need DAG file to be loaded into card's memory. DAG file grows in time. So when (and if) it will superpass 4GB - you could mine no more with these cards. Current Eth DAG size is ~2.3Gb. 4Gb is expected roughly on 06/FEB/2021 - after that date you will not be able to use 4Gb cards to mine Eth (and Im not even considering PoS here)