All About BTC, LTC, ETH mining as well as other alternative crypto currencies
We’ve managed to get our hands on an AMD Radeon RX 470 video card and not just any, but the best out there – the 8GB Sapphire NITRO+ AMD Radeon RX 470, so we’ve had to put it to a test to see how good it will perform for mining Ethereum (ETH) and other popular crypto currencies using different mining algorithms. The Sapphire NITRO+ 8GB model of RX 470 is probably the best you can get in terms of mining performance among other RX 470 offerings because it comes with memory clocked at 2000 MHz (8 GHz) or with other words the same memory frequency as the reference design RX 480 GPUs.
This faster video memory makes it interesting especially for mining Ethereum, but there are other good points to that video card as well such as the 8-pin PCI-E power connector, the good cooling solution and the 1260 MHz boost clock of the GPU. The only drawback is that the price of the Sapphire NITRO+ AMD Radeon RX 470 8 GB should pretty much be the same as the price of 8 GB reference design RX 480s. The 4 GB models of RX 470 are apparently equipped with slower memory, so as far as Ethereum mining goes they will perform slower than the 8 GB NITRO+ version, though i other algorithms they may not be much slower.
The hashrate that the Sapphire NITRO+ AMD Radeon RX 470 8GB manages to provide out of the box for mining Ethereum is about 24.5 MHS or almost much what the reference design Radeon RX 480 manages to deliver mining ETH. Again this is because of the 8 GHz video memory used on that model from Sapphire, other RX 470 cards with 4 GB come with 7 GHz or 6.6 GHz video memory and that will for sure result in a slower hashrate for Ethereum. The Sapphire NITRO+ manages to keep just fine the GPU boosted to the maximum 1260 MHz is supports all the time, though for Ethereum mining you can lower that frequency by reducing the power limit below 100% on the Power Target as ETH does not benefit much from the higher GPU frequency and you can reduce the power usage without a hit in performance.
What we did not like much is the default fans profile that try to keep the rotations per minute at a low value maintaining a silent operation of the GPU, but with it working at higher temperature. While mining Ethereum the RX 470 wanted to keep the fans in the 30-ies as percentage or about 1300 RPM and as a result the temperature spikes above 70 degrees Celsius, so manually increasing the cooling temperature curve or setting a fixed higher percentage is a good idea to keep the GPU cooler while mining, especially if you mine coins that use more GPU intensive algorithms unlike the one used by Ethereum that is more memory dependent. Also the default power usage of the Sapphire NITRO+ can definitely use some tweaking as it seems to be slightly higher than that of a reference design RX 480
Overclocking the Sapphire NITRO+ AMD Radeon RX 470 8GB has left us a bit disappointed. We kind of expected to be able to push the 8 GHz video memory to at least 8.8 or 9 GHz like you can on most reference design RX 480. Unfortunately we ended up with up to 8.2 GHz (2050 MHz) maximum limit from AMD’s WattMan and maximum 8.4 GHz with the use of the ASUS GPU Tweak II tool. We are still somewhat short on options for overclocking tools for the new AMD RX series of GPUs, so this forced overclocking limit has left us disappointed. We are not sure if it was forced because the GDDR5 memory chips from Samsung are not capable of working at higher frequencies without problem or as a safety measure so that the RX 470 turns out slower than RX 480 even when overclocked.
The result of the limited video memory clock is important only for Ethereum mining as the result is slower maximum hashrate. At the maximum of 8.4 GHz (2100 MHz) for the video memory we were able to get just about 25.8 MHS mining Ethereum or with other words just about 1.3 MHS more than the stock clocks hashrate. We are yet to see how the 4 GB models of the RX 470 will perform with Ethereum due to their lower default video memory clocks as well as how much it will be possible to overclock them.
When the AMD Radeon RX 480 was released there was an issue with the drivers that prevented users from successfully mining many of the crypto currencies that used sgminer as the miner just crashed with an error. Since the RX 480 was actually a new architecture there was no way to just get back to older video drivers and have no trouble running sgminer, however it seems that the situation has improved significantly since then, though it is still not perfect for some algorithms and miners. Since at that time most people were using RX 480 for Ethereum mining where no problems with the miners were present that was not much of an issue, but due to various reasons a lot of people have since moved to other alternative coins. Above you can see the hashrates for many of the more popular algorithms supported by Nicehash and tested with their dedicated mining solution that bundles multiple miner programs in a single package.
You can see some benchmarks of the AMD Radeon RX 480 using the NiceHash miner here and note that quite a few of the algorithms back then reported 0 MHS hashrate. At the moment it seems that only Neoscrypt, WhirlpoolX and Blake256r14 are still problematic and are reporting 0 MHS hashrate. That is of course only for the listed algorithms supported by NiceHash and there are quite a few others as well. It is important to note that the Sapphire Nitro+ RX 470 8GB is getting pretty close in terms of performance to a stock RX 480 with 8 GB and in some cases the results are even slightly better (due to further optimizations) and in the others the performance is not behind by much. Still the presence of a little more Stream Processors in the RX 480 gives it an advantage in the more GPU intensive algorithms compared to the RX 470. Unfortunately the GPU frequency of the RX 470 cannot be pushed much higher like on the RX 480, so hoping to compensate the difference with higher OC will just not do.
Just to add information about some more algorithms, the LBRY sgminer crashes the video driver, so we could not get a result in terms of hashrate. As for the SiaCoin sgminer, it has managed to provide us with 906 MHS hashrate mining on the Siamining pool using Stratum, so there were no problems with that miner. Hopefully the issues with some miners and some algorithms not working with the new AMD RX series of GPUs will be resolved as AMD is probably already preparing the faster RX 490 for a release alter this year and it is highly likely it being an interesting solution for crypto miners as well.