The FTW card is heavily overclocked at stock. It will probably do 2025 MHz for the GPU without touching anything other than the power limit. As ED said, most of the 1080s are topping out around 2100 MHz for the GPU boost clock.
I have a FTW, and it tops out about 2150 MHz.
When you are overclocking, it's the sustained boost frequency that matters, not how much you add to the GPU overclock slider.
The FTW has 2 different BIOS on the card. The standard one which raises the power limit to 120% max, and the second one that raises it to 130% max. If you want to overclock the card, you need to use the secondary bios (the higher power limit stabilizes the GPU boost clock...versus it jumping all over the place.) To enable this BIOS, you need to power off the computer, move the switch (it's little, and the words "master/slave" are on the GPU backplate). After you move the switch, you need to remove AC power from the power supply and wait about 10 minutes (the capacitors on the FTW card have to fully discharge).
Reboot your PC, and you will be able to set the power limit to 130%.
Overclocking your card will cause it to get hotter. So, you should setup a custom fan profile. For me, I just keep the fans running at 90% all the time (the ACX 3.0 cooler is very quiet).
When I dial in my overclock, I keep the Heaven benchmark running continuously and increase the GPU slider by +25 MHz after it makes it through each pass. You should wait 1 pass on the Heaven benchmark to let the card heat up before increasing GPU frequency. When you are overclocking too much, you will see artifacts on the graphics display, Windows will report a graphics driver crash, or your PC could just lock up. For everyday use, when I find the max overclock, I have my "daily" overclock be about 25 MHz lower.
If you want, then repeat this process with the memory (although memory won't give you as much of a performance boost). Start with a 100 MHz increase on memory frequency and then increase in 50 MHz increments until you get artifacts, display driver crash, or Windows crash.
As you are running a multi-monitor surround setup, the GPU will never fully downclock when idle. Mine never goes below 1731 MHz idle. If this bothers you, you can install NVIDIA Inspector software (free) and enable the extra power savings mode.