The link goes into a lot of detail on exactly the best way to get an overclock with little or no power limiting using a custom voltage curve.
Edit: I was testing power limiting with the Arctic Storm BIOS. I found at 2025 core, 6177 memory at .993v my card does zero power limiting in Fire Strike Ultra, Time Spy and Superposition 4K.
Also, it won't power limit on the Fire Strike Ultra stress test. Every BIOS I've tested so far seems this is true at .993v under water.
My temps on a 360 RAD with a highly overclocked 5960x and my 1080 Ti never go above 43C on the GPU at these settings.
But a lot of that is adding Fuji 17.0 W/mK thermal pads on the memory and VRMs and a few other key places.
Normally I run 2088 core, 6077 memory because I have a 4K G-Sync monitor and I cap games out at 59 FPS to keep G-Sync enabled and capped at 59 FPS it does no power limiting at 2088 at the highest graphics settings in games.
But if you run higher frame rates or have a 144Hz monitor and run it at cap you may want to consider your max clocks at .993v.
Under water is great and under air it will greatly reduce temps and thermal throttling you may encounter as well.
Also if you are getting 'Display driver has stopped responding' do below. It works for Windows 7 to Windows 10.
Before you start running Heaven these settings in Nvidia control panel, it'll make your overclock more stable. Also in any game use Single Display Performance Mode and Prefer Max Performance, your games will be more stable with your overclock and have a more constant FPS.
Next you want to CTRL F in Afterburner, open the custom voltage curve, CTRL D to set it to defaults. Then you want to hold Shift, drag it to say +145 1999 core at 1050v and hit apply in Afterburner
It'll run around 1999 core at 1.062v in Afterburner in Heaven. Don't run Heaven though, drag the 1031v point up without holding Shift to the same as the 1050v point and hit apply.
If you do it right everything to the right of 1031v should be in a straight line.
Try lower voltages if you are on an air cooler and want to keep temps down, though you may need to start with lower clock speeds as well.
Keep your memory between +400 and +500 to start even if you can do more.
Crappy video I made how to actually do the custom voltage curve.
It's how to do a 1.093v voltage curve, to do 1.031v you need it to look like the voltage curve picture farther down this guide.. Since I flashed the Strix BIOS on my FE I'm getting 2100 at 1.093v with no throttling.
Open Heaven at a lower resolution than your screen resolution NOT in full-screen mode so you can still see Afterburner.
When you run Heaven if you get no driver crashes or screen freezing about three seconds and restarting that's good. Now raise the 1031v point with Heaven running one notch at a time to high core speeds like from +145 to +155 and hit apply, then between each time wait 30 seconds or so.
Keep doing this until the driver crashes or screen freezes three seconds and Heaven restarts. Close Heaven then drop in back down one notch, hit apply, and reboot. Your frame rate and stability will be compromised until you reboot.
Now do a full benchmark run with Heaven. If nothing crashes core is good. If driver crashes or screen freezes just drop it down one more notch. At 1.031v max core you can get you should get zero drops in voltages and core speed, should stay at 1.031v and the core it's at.
You can have GPU-Z running and logging to see your core does not drop during the run and be sure you had no driver crashes. If core and volts drop drastically a few seconds, then resumes, your driver crashed.
Ideally, this is what your final voltage curve should look like, but with the maximum core you determine by this method.
After you get best voltages with maximum clocks drag each point in your voltage curve without holding Shift until it looks similar to this.
After you get core stable run Heaven and hit Shift to pause it at a scene. It'll show the frame rate up top with screen paused. Stop it at a lower frame rate scene when the frame rate only fluctuates a few FPS while paused, usually a scene with no clouds or smoke or anything.
Now adjust your memory up/or down until you get the frame rate as high as it'll go with no driver crashes or artifacts. HIGHER ISN"T ALWAYS BETTER. I find at +642 is a few frames slower than +610.
Your frame rate may only be higher a few FPS at best memory speed but that's fine.
You have now found a low voltage best clock speed compromise for your water/air cooled 1080 Ti.
Being obsessive about these things, I've found under water, no shunt mod, voltage slider maxed out, the trick is to find the best clock speeds you can obtain at the lowest possible voltages for sustained voltages and core speeds.
If I run my core at +177 2062 at 1.031v I get a solid 1.031v and 2062 core on a full 1920x1080 Heaven run. This is the lowest I can go on voltages with zero driver crashes at +177 core.
If you look at my GPU-Z log not once did I dip below 1.031v or 2062 core.
With 2093 core 1.093v it bounced up and down from 1.050v to 1.093v and in between, clock speeds changing as it does of course.
So while you can brag about maximum clocks (I got 2100 benching) for every day 24/7 scenarios a balance between voltages and clock speed seems to be key.
Hope this helps some. I'm reluctant to do the shunt mod as in my case my video card sits vertical and I'm not going to have the CLU run under my EK block and ruin my card.