@SGaist
My data is ready to append. So i append them directly. There are 10-100 QTextEdits. I append 100-200 line to each of QTextEdits. Lines have arround 300 characters. I have one vector of vectors source.By the way, i moved my data source to a different thread. Then emitted signals to append with BlockingQueuedConnection. Gui is responsive now. But its not smooth. I dont know using blockingqueuedconnection instead of queuedconnection is the right way but my gui is responsive while appending strings now.