it is true bensam. i tried on my old wonky miner and it shows the same drop. dunno if it's exactly the same issue, afaik AMD arch doesn't even have a TLB. now let's see how that 1070 holds up 
Yes this is true... Something else to remember is Ethereum profit on a 480/580 isn't just limited to Ethereum, when Eth starts earning less you start cranking the intensity up on the secondary algo (PASC/DCR/SIA), just the same as mining with a 1070 or any piece of Nvidia hardware, only AMD has the assembly changes which almost double the secondary algo earnings compared to Nvidia (which is why it would be nice if someone made a good dual miner for Nvidia).Seems as though everyone is freaking out on the lost revenue, but one of the reasons you buy say a 580 over a old school R9-390 off eBay is because it performs better when you take into account other algos.
The latest claymore can do 30-32MHASH ethereum and 1000MHASH decred (-dcri 20) on the r9 390 But the power usage is 340watt.
I am dualmining eth at 27-28MHASH and 1000MHASH decred or 500 mhash sia @260 watt (with a homemade bios mod).
Profitable, but use too much fuel compared to NVIDIA cards or 470-580 cards.
With the bios mod, I can run 6 390 cards on a 1700W psu.