Himself wrote a serial assistants, always with a very comfortable, but recently met a problem, I quickly back to the MCU a large amount of data has been stuck, so I use XCOM regularly sent to do the test, the results found that the Rx display the number of receiving and XCOM send number is consistent, i.e. no missing data, just slow TextBrowser display refresh, the current process is triggered by the readyRead signal receiving display function, and signal dataRecieved trigger display function, and has set up the biggest display text TextBrowser

 UI - & gt; TxtBro_recieveBox - & gt; Document () - & gt; SetMaximumBlockCount (128); 

Every time when you have obvious effect of the received data is less, but if every time the received data more after a period of time will still be jammed, if there is a solution to your bosses,