It is not rocket science that the longer a cryptocoin is being mined, the more is the mining difficulty and thus the less is the profitability. In the case with Ethereum, the mining performance decreases over time due to the increase of the DAG file size. More size puts more stress on the mining GPUs, which lowers their efficiency.
However, this is only part of the story. The real issue is that a great drop in Ethereum hashrate is expected for Radeon RX 400 / RX 500 series in the next couple of months. By ‘great’ I mean up to ~30% hashrate drop, which will increase gradually.
What Are the Causes?
According to statistics, users mine 30.000 blocks every 4-5 days. This amount of blocks is called a DAG Epoch. Every time we move to the next DAG epoch, the DAG file becomes larger. This means that weaker GPUS will have a harder time handling it. We are currently at DAG epoch #130. Once we hit DAG epoch #150 or so, the increased size of the DAG file will cause RX400 / RX500 GPUs to work with about 30% less efficiency. Since the file size growth is gradual, the performance decrease will be gradual too.
Did this happen before?
Yes, indeed. If you remember, the AMD Radeon R9 280X GPUs suffered from the same kind of hashrate drop past year. Looks like the RX 400 / RX 500 are next in the list. Now, the newer and more powerful cards such as Nvidia Pascal GPUs, as well as the R9 290(x), / R9 390(x) that feature more video memory (6GB/8GB+) won’t be significantly affected.
I see the speed drop. I checked possible workarounds, at least for Polaris, they failed. So probably this hashrate drop cannot be fixed, at least on miner software level.Claymore
What Is the Takeaway from This?
First of all, you might want to consider newer GPUs for any future rigs you are going to build instead of the classic Radeon RX400 / RX500s. Or even if you are going to use them, it might be a good idea to include the 30% hashrate drop in your profitability calculations.
The second takeaway is that after all, video memory matters. GPUs with more video memory tend to stand the increase of DAG file size longer. Next time you’re getting a new GPU rig, you might consider the GPU memory amount; even though it might not affect the hashrate at first, it might add to the card lifespan.
GTX 1060 Series 17-22 Mh/sGTX 1070 Series 25-30 Mh/sGTX 1080ti Series 28-32 Mh/s
Finally, if you want to test your rig and check how it will be affected by the DAG epoch changes, you might want to do this:
Go to the Claymore ETH miner and add this option: –benchmark 130
Then, change the number to 140, 150 or 160 and see how this affects the hashrate.
Here is my test with 5x Sapphire Nitro+ RX 470 4GB OC
sorry for the bad news 🙁
Hopefully there is Ethereum Classic, UBIQ, Expanse, ZCash, Monero and many more profitable altcoins waiting to be mined 🙂 so.. heads up!
Let me know what are your results while testing your rigs.
Thank you for reading. As always, your comments, suggestions and questions are welcome.
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