It depends on GPU, settings, selected coin, it's price and net diff. For example, for SIA on stock 1070 ccminer shows 1400MH/s. In dual mode in v9.7 I get 650MH/s SIA (so 45% of pure SIA speed) with only 2% ETH lost (about 25.8MH/s instead of 26.4MH/s).
DCR speed is not so good, agreed.
After seeing this comment I spent some time today testing my 1070's with different -dcri settings. I wasn't getting anywhere near that SC hash. About 30.6mh/s eth and 309mh/s sia with default -dcri 30.
While testing on my main PC, I came to the conclusion that a -dcri 60 was about the best trade off for loss of ETH hash vs. gains of SC hash. I was now getting around 29.5mh/s eth and 660mh/s sia.
I moved these new settings to the mining rig and the ETH hash just tanked. Checking around I noticed that the cards wanted to draw more power with this new -dcri setting. The 1070's in my rig are overclocked and the power was decreased. Originally when I set up the rig, I tested the miner with ETH only and found I could get away with 75% power on the cards with no change to hash.
Increasing the -dcri seems to require more power. I tried pushing the power to 112% and the hash rates just flew. 29.6mh/s and 693mh/s respectively.
Seems like quite a lot more power for that extra SIA hash. Just posting as it's something people might want to consider.
TL;DR
-dcri 30, 75% power = 30.6mh/s eth, 307mh/s sia
-dcri 30, 112% power = 30.9mh/s eth, 309mh/s sia
-dcri 60, 75% power = 24.5mh/s eth, 490mh/s sia
-dcri 60, 112% power = 29.6mh/s eth, 693mh/s sia
Did you try experimenting with core clocks while dual mining? I found 75dcri with a higher core clock for my 1070's gave me higher results for both ETH/SIA at the cost of even more power. In the end I just decided dual mining wasnt worth the added power, heat, and stress along with the 2% eth tax.
