Comments by mikanu (Top 2 by date)

@Çağrı Daşkın if you're running the capture on a background thread and updating UI using BeginInvoke and it's still not responsive it might be because you're making too many calls to swap the image in the picture box. A better option might be to buffer the most recent image from the PictureBox and then have a timer on the UI thread update the picture box every so many frames. I'll post another answer as this is a different technique.