Can someone explain me how to tighten memory timings

Soo basicly my RAM knowledge is 0, as i have HyperX 8GB (2x4) running at 1600Mhz i would like to tighten ram timings, as you may see in pictures could you explain me how to do it?
Thank you for your time.

Memory.png

SPD_tab.png
 
Solution
You can change them, but that doesn't mean it will boot or run stable... If you manually change the timings, I would run memtest86 overnight before I trusted it.