vb.net scrolling a picture at same speed or same performance in 3 computers

Question

i am designing a game with 3 computers to show a picture (1920 x 3000pixel at 1.4Mb size) scrolling on screen from top to bottom. My requirement is to require all computers to scroll to the bottom at the same time or 0.5 seconds difference between them.

firstly, i tried
do while until end of picture, thread sleep in loop to have scrolling effect
but the result is not satisfied. the difference between computers is up to 15 seconds

secondly, i tried
timer to scroll the picture until to the bottom
but the result is better but still not satisfied. the difference between computers is up to 6 seconds

any advice to do it? regardless of controlling scrolling speed, can i design in another way by scolling the picture within 40 seconds, the program control the speed by calculation.

Besides, i found when i run these kind of loop repeatedly. The result seems much better. the computer seems to adjust its CPU to run at full speed but my game does not run the loop repeatedly

Possible to set CPU speed by VB? Thanks a lot.

Answer 1

If you scroll the picture by adjusting its location, then try this code:

Dim FinalTime = Now.AddSeconds(40)

Dim t As New Thread(Sub()

                        Dim y As Double = Y1

                        Const dt = 20
                        While True

                            Dim iy = CInt(y)

                            Dim t1 = Now

                            PictureBox1.Invoke(Sub()
                                                    PictureBox1.Top = iy
                                                    PictureBox1.Update()
                                                End Sub)

                            If iy = Y2 Then Exit While

                            Thread.Sleep(dt)

                            Dim dy = (Now - t1).TotalMilliseconds * (Y2 - y) / (FinalTime - Now).TotalMilliseconds

                            y += dy
                            y = Math.Min(Y2, y)

                        End While

                    End Sub)

t.IsBackground = True
t.Start()

where Y1 is the initial vertical position, Y2 — the final vertical position of the picture (Y2 > Y1), 40 — the duration of the animation (seconds).

Answer 2

the 3 computers of same model can be completed at that time by adjusting process priority to high.

amazingly, another older computer run faster than the 3 new computers

Thanks all for teaching me