Hi, I have seen some videos that the printer prints in a rapid speed put mine into a shamefully snail pace. What do I need to do to make everything faster?

There are a lot of factors can affect the printing speed, frame, frame material, frame design, motors, extruder design, calibration and other stuffs

What is your usual print speed?

Mine using slic3r at 60mm/s although at other part of the object it will become slower like outer perimeter and first layer

Higher speed will often gives you disaster in your finished product

Print a 100 x 100 x 5 mm high solid block, and slowly up the speed to see how high you can get.

Anything you can do to make your frame more ridged or your x carriage lighter. Switching to a Bowden would be one way to shed a LOT of weight. Making sure all your belts are tensioned right, your screws are tight and everything is generally calibrated and in good condition.