So I have the exact same problem. However I have 2 different machines. One is using a micro atx amd motherboard and has 2 gtx 1070s in it. It averages around 60 mh with nicehash daggerhashimoto and claymore. (good)
My second machine I am in the process of putting together. Right now I have 3 gtx 1070's in it. It has a msi z170A mobo and G4400 cpu. and 4 gb of ram. This machine gets a total of maybe 7-8 mh with nicehash daggerhashimoto and claymore. (bad)
The second machine seems bananas that its so low. If i mine other cryptos on the second machine they work fine.
I guess its possible it has something to do with my windows install. I have not tried swapping the ssd's. But I tried making the swapfile larger. That did nothing.
I am worried that it is something like the cpu or the memory or the mobo. That the etherium miners dont like.