Response time option can be selected under different View Mode.

Viewmode => Standard => Response time => Standard / Advanced / Ultra fast 

Viewmode => Game => Response time => Standard / Advanced / Ultra fast

In both cases, while selecting the “Advanced” or even “Ultra fast”, it brings a very strong ghosting effect and blurry while scrolling up and down a page.

There is always trade-off. When reducing response time, it means the monitor will have less time to process the signal it receives. 

So the picture/video performance will be impacted.

In a word, what response time settings should be chose depending on user’s preference. 

If no particular needs on response time, it is suggested to set it as standard.