Most of the time i use Adobe Reader to read pdf files and i always find the font rendering very bad as shown below. This example is very bad as there are some bold texts in those paragraph but i seen none at all.
After looking through the preference settings, then i realize that there is one setting that i never set properly. To go to this setting, you first go to "Preferences"
And on the Preferences window, go to Page Display and look for Rendering section. As you can see, under Smooth Text, my setting is "none"
So i change it and set it to "For Laptop/LCD screens"
And the end result, finally a smooth rendering text and bold text is obvious. :)