Shift-Click The flag to turn on Turbo Mode. Turbo mode is STRONGLY recommended. Hide the prime numbers list if you are going to do anything over 10000. It makes things faster. Numbers at top of screen will always move, press space to update the loading bar and variables at the bottom of the screen.
Everything By Me I have had this calculate all the prime numbers up to 1000000 (for some reason it only calculated up to 999954) and on screen, there is every single prime number from 1-1000000 the loading bar will not work if you press space though.