When I run the GUIMark2.Bitmap test in auto mode with the latest jdk7 on Mac I get the instant FPS measurement to vary from 30 to 60, which is quite visible by itself.

% java -cp "../../../artifacts/sdk/rt/lib/jfxrt.jar:dist/GUIMark2.jar" guimark2.BitmapTest -monsters 3000 -auto
auto: true
monsters: 3000
alwaysmove: false
usefrontback: false
JavaFX: using com.sun.javafx.tk.quantum.QuantumToolkit
Warming up for 10000 ms
FPS: 24.99
FPS: 37.82
FPS: 43.99
FPS: 40.57
FPS: 38.95
Warmup complete, starting scoring run (20000 ms)
FPS: 51.98
FPS: 46.93
FPS: 44.99
FPS: 50.78
FPS: 48.41
FPS: 47.68
FPS: 38.73
FPS: 50.69
FPS: 30.78
FPS: 42.87
Score: 43.02 FPS