When calculating what crypto coin to mine you need to take into account not only the hashrate you get, but also the power usage for the specific algorithm used by the coin. When talking about Nvidia GPUs the two most popular ones used by miners are GTX 750 Ti and GTX 970 and there is a reason behind that – they offer good price/performance ratio to be used in multi-GPU mining rigs. Sure you can always go for a GTX 980 Ti or even GTX Titan X, but these although more powerful are also significantly more expensive and do not provide so good price/performance ratio.
We have decided to do a quick check of the current situation with a Geforce GTX 970 video card from Gigabyte (WF3OC) and a GeForce GTX 980 Ti reference design GPU and see how they compare in a power and performance check. The results you see in the table above are achieved with the latest ccMiner 1.7.4 from Tpruvot and with the latest fork of ethminer wth CUDA support from Genoil. The video cards are not overclocked further than their factory settings (the Gigabyte GTX 970 is factory overclocked) and they are forced to run CUDA applications in P0 power state to maximize performance in Ethereum.
As you can see from the results aside from Ethereum the GTX 980 Ti is faster with not that much more power usage, however the price of the 980 Ti is roughly double the price of a single GTX 970 and with two 970s you are sure to beat the hashrate of a single 980 Ti. It is interesting to see that a GTX 980 Ti (reference board) can be slower than a GTX 970 GPU, but with a non-reference design you can actually get about 20-21 MHS in Ethereum due to the higher clocks. Still the GTX 980 Ti is most definetly not the right video card for mining Ethereum, if you want to stick to mining Ethereum’s Ether coins with Nvidia you should go for the GTX 970 for sure as the best choice. Even though for Ethereum and other Dagger-Hashimoto altcoins AMD GPUs are still faster in terms of hashrate.