Best settings, Undervolting cards for ETH + SIA mining ? (gtx 1070ti / 1080)

[Mydi]

Hello,

I'm currently dual-mining eth+sia on two different computers. One has a gtx 1070ti and the other a 1080.

I'm trying to find the best parameters to get a good hashrate on both, while also reducing heat/noise/power consumption. And lastly, since the computers are also used for gaming and day-to-day usage, I'd prefer if I do not have to change the cards settings whenever I stop claymore to do something else.

For now, the cards are set up as:

1080:
power limit: 70%
memory +700
core - 400
temp ~68 and fan ~60
eth: 24.7 mhs
sia: 850 mhs

1070ti
power limit: 70%
memory +500
core 0
temp ~68 and fan ~60
eth: 30.7  mhs
sia:  650 mhs

I'm fine with the temperature of both cards but would like to reduce the fan to reduce noise and reduce their power consumption a bit if possible (w/o lowering too much their has rate).

Here are my questions:

1) I could not reduce the core clock of the 1070ti w/o suffering a heavy loss of hashrate (in both sia and eth). I don't really know why it is because it seems that the card should be able to handle it even at -400mhz). Any idea why ?

2) I couldn't find a definitive answer, but do core clock matters for SIA mining? I did not find much difference between a -400 settings and a +100 for my gtx 1080 for example.

3) Regarding undervolting. Isn't the power limit factor supposed to already take care of it ? If yes, is undervolting a bit really useful ? If no, kind of undervolting would you suggest for these cards? Would it affect my gaming sessions much ?

4) Any tips ^^?

Thanks everyone !