I have the Asus Strix 1080ti Gaming OC (O11G) I have been testig OCing it without corevoltage , only max power option. Did any one OC'd his 1080ti (Clock and Memory) I have managed to reach a boost clock speed of 2050mhz. Stable with testing till now:

The Evil With In 2 (2160p , Ultra , FXAA) and Mass Effect Andromeda (2160p , High / Ultra Setting Mix , FXAA). Evil with I In 2 min Fps 45 and it reaches 60 , average about 50 and Same for Mass Effect)
The power option will automatically allow the card to consume more power. Of course more power will cause the card to run hotter. As long as card is stable and is within acceptable temp range, you should be fine. A 2000Mhz OC is impressive as not all cards can achieve that.

What is the FPS difference before and after the OC?
Yes mate a noticble difference , I usually play 2160p High to Very High Setting without AA on very demanding titles such as Mass Effect Andromeda the min fps is 45 fps reaching 60fps , when I OC'd the 1080ti Strix Gaming OC the Min Fps pushed to 53 fps with enabling AA too (FXAA) , on average you will gainn 8 fps without sacificing on the image quality - High to Very High Settings (Including Shadows and HBAO +). Very playable experience on native 4k with very good image quality.






Strix coolig is great , A top notch 1080ti performer.