I guessed it is not a new issue in 4.0b Beta 7 because I just switched to beta yesterday. I tried to do some Chinese search and have found that it is significantly slower than English Search. An example is to search 約翰 in the Chinease Union Bible (Traditional Script) using Bible search.
After pressing the enter key, each hit slowly appearing one by one as if it is in slow motion although it says 155 results in 149 verses withn 0.04 second. The situation is even worse in the Verses view and Grid view. In these two views when I try to scroll down the hit results, Logos 4 seems to freeze for a while before the hits appear. To me it seems the PC has difficulty to draw up the Chinese Hits quickly.
The issue should not be a hardware one because I upgraded my PC for Logos 4 and no similar issue found when I search in English and Hebrew.