It Is All About BTC, LTC, ETH, DOGE, KAS mining as well as other alternative crypto currencies
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.
Do you remember how last year AMD Radeon R9 280X GPUs started dropping in terms of mining hashrate for Ethereum due to the growing DAG file size? Well, it seems that we are in for the same thing happening with the Radeon RX400/RX500 series of GPUs with 4/8GB VRAM in the next couple of months. We are currently at DAG epoch #129, but in the next 30-35 or so DAG epochs we are going to be seeing gradual drop in hashrate resulting in up to about 30% decrease from the current hashrate on the Radeon RX400/RX500 series of GPUs. It seems that other more powerful GPUs such as R9 290(x)/390(x) as well as Nvidia Pascal GPUs with more video memory (6GB/8GB+) will not be affected or the drop in performance will be much smaller to a level considered pretty much insignificant compared to what will happen with AMD’s Polaris GPUs.
You can easily check what will happen with your existing GPU mining hardware and if it will be affected in terms of performance and how much by adding the option -benchmark 130
to the Claymore ETH miner. Change the number 130 (the next Ethereum DAG epoch) to the DAG epoch you want to test with such as 140, 150, 160 and see how your hashrate will change or if it will change. The Ethash DAG changes every 30000 blocks which is roughly every 4-5 days and with Ethereum this is called a DAG epoch, so every few days we move to the next DAG epoch. As DAG epochs move further on they also grow in size and put more stress to the video cards that are being used for mining and as a result there is also some performance drop observed over time. The more powerful the GPUs is and the more video memory it has, the more likely it is to be able to handle better long term mining Ethereum.