(Sorry for my bad english.)
If you want to get more FPS:
1) Use Optifine for a better Minecraft performance. (
https://optifine.net/home)
2) Go to the settings and acitvate "Advanced settings":
Change the JVM arguments from "-Xmx1G" to "-Xmx4G" (if you have 8GB or more RAM) or to
"-Xmx2G" (if you have 4GB RAM):
3) Change the Recording Priority in Bandicam: