Hello,
 
So I added a 2nd GTX 1080 (EVGA hybrid reference design) to my rig yesterday, and while my first card (an nvidia fe on hydro copper)I considered a decent overclocker (getting to 2014/5600mhz on boost). The 2nd has surprisingly been amazing, getting to 2190mhz/5600hz on boost clock. Neither cards have any bios mods etc, but I have been having hard time trying to get them to both stick to the maximum SLI capable clocks. Both cards have a linear curve which puts the 1093mv clock to 2114mhz and 596mhz addition on the memory slider in precision xoc with 100% voltage offset, I know both cards individually are 100% stable on those clocks, everytime I set them up like that in link one of the cards core clock slider would get back to 0. Linear mapping on the curve at same point and clock should match 100%, I've searched quite a bit but haven't found a way for this to be done without using the basic slider increase.
 
I have tried MSI afterburner with the same results. Aside from this, I was wondering there was anyway to get my first card closer to the 2nd one using another bios? since the temps on fe at max load stay under 39c. I'll be adding the 2nd card on hydro copper too shortly, but I am not expecting the temps to go too much higher. Thanks!

I'd assume you're going to have to to do two custom curves.  Put the faster card in slot one, and tune it the best you can.  Store that curve and then install the slower card in slot two.   Bring up the curve of the second card, and push until you crash.  Back down a bit and that will be your SLI max.  Stuff that uses SLI will run the cards at that max setting, and stuff that isn't SLI aware will use the faster card and push it to it's solo max.
 
SLI is tricky to find the max for without testing the cards separately, but if your above 2000 on both cards, and holding there I'd say you are in pretty nice territory.
 
 

Must be really nice to have SLI and then go more power and overclock them. I probably would leave well enough alone since just SLI would be able to crush any game. Of course I also would get that wild hair to see how far I could take a benchmark. Thanks for posting the results.