> NVIDIA GPUs are actually typically more efficient for mining most coins, AMD cards are only preferred because they have quicker ROI.
In what way are nvidia cards more efficient? Vegas are in some cases much faster and at worst equal to gtx 1080.
In what way are nvidia cards more efficient? Vegas are in some cases much faster and at worst equal to gtx 1080.
The usual way, i.e. "efficiency=performance/power"? Here, I did the math for you. Numbers from whattomine.com:
https://i.imgur.com/2u2HOw7.png
https://filebin.net/fr1sqfwtvulkoynu/gpu_efficiency.ods
As you can see, apart from Vega being a very efficient Cryptonight miner, and Polaris being an acceptably efficient Ethash (Ethereum) miner, AMD cards have absolutely garbage efficiency, they use just tons of power for their performance. And they are one-trick ponies: there are only one or two decent algos for AMD cards.
The 1080 and 1080 Ti specifically have problems with a few algos due to their GDDR5X (which results in half of the memory bandwidth being wasted) but on the whole NVIDIA cards are extremely efficient miners across a variety of algorithms, and usually keep up with AMD on efficiency even on Ethash.
The 1070 Ti, in particular, is the reigning champion of efficiency. It's basically a 1080 with GDDR5 instead of 5X, which makes it the most efficient card in most algos, and its worst-case is "only" being as efficient as a 580 at Ethash.
Again: people prefer AMD cards because they ROI quicker during the booms. The half of this that efficiency obscures is power: AMD cards have higher TDPs and are capable of pumping out a lot more watts per dollar (RIP Planet Earth). But when profits are down and efficiency matters (or for those with expensive electricity), NVIDIA is better, and you also have that flexibility to move across algorithms if there is a hot new currency.
There is also a pretty substantial cargo-cult with regards to mining: people use AMD because that's what they see other people using, and they don't bother to do the math. But NVIDIA has the same efficiency advantage in compute as they do in gaming: 1.5-2x the performance-per-watt in most situations.
https://www.techpowerup.com/reviews/Sapphire/RX_580_Nitro_Pl...
https://www.reddit.com/r/EtherMining/comments/674evm/rx_580_...
Again: AMD is way, way behind on efficiency and has been since Maxwell. There are a few algos they do well on, but on the whole they are roughly a generation to a generation-and-a-half behind NVIDIA (Vega 56 is roughly as fast and efficient as a 980 Ti). You buy them because they're cheap for the hashrate, not because they're efficient. Think cheap-and-nasty here.
The thing with AMD power measurements that you have to be real careful of is that AMD's sensor is only reading the core power, not any power spent on memory or any losses in the VRMs, and they do it very inaccurately (and don't account for efficiency/etc). So you should be taking people's chatter on Reddit with a big grain of salt - unless you are measuring the power at the wall, or using a digital PSU, you are probably getting figures that are ~40W low, and potentially have 20% variation or so from the actual figure. Anyone using GPU-Z to measure their card is doing it wrong.