If you remember last month we have warned that a possible Ethereum Hashrate Drop for Radeon RX400/RX500 GPUs is Incoming. The slow decrease of mining hashrate for Ethereum (ETH) on AMD Polaris-based GPUs was a bit puzzling as it was actually not related to the video memory, so 4GB and 8GB models were affected. Do note that at some point though cards with 4GB video memory might still start dropping in terms of mining performance anyway as the DAG size starts getting close to the amount of video memory available.
It turns out that AMD may actually be working on a driver fix to resolve the problem according to information published by Claymore on the Bitcointalk forum. Apparently the upcoming AMD Vega was also affected by the same problem, though it has been already resolved with driver fix and in two weeks or so a fix for Polaris may be release via a driver update as well. Hopefully a driver update that will not be WHQL and allow the use on AMD GPUs with modified video BIOSes as most AMD Polaris-based Ethereum GPU mining rigs are using modified memory straps for better performance.
On a side note, something regarding AMD’s new Vega GPUs for mining Ethereum from Claymore, in case you have missed it:
“Vega is … hot. In stock it takes about 400-450W in dual, 300-350W in ETH-only mode at about 33MH/s. And it’s throttling like hell. It’s very good in dual mining mode, but it’s too hot.”
So most likely the new AMD Vega GPUs will not turn out to be a great choice for mining, though who knows… people are using GTX 1080 Ti’s at 250W TDP or even more with some OC for mining and are happy with the results. Even though it might not be great for mining Ethereum, the new AMD Vega, just like with GTX 1080 Ti, might still end up a good solution for Equihash or any other popular altcoin algorithm for example.