diff --git a/ArduCopter/config.h b/ArduCopter/config.h
index a174948d62..9d8070b11f 100644
--- a/ArduCopter/config.h
+++ b/ArduCopter/config.h
@@ -59,7 +59,6 @@
  # define CONFIG_IMU_TYPE   CONFIG_IMU_MPU6000
  # define CONFIG_SONAR_SOURCE SONAR_SOURCE_ANALOG_PIN
  # define MAGNETOMETER ENABLED
- # define MAIN_LOOP_RATE    100
  # ifdef APM2_BETA_HARDWARE
   #  define CONFIG_BARO     AP_BARO_BMP085
  # else // APM2 Production Hardware (default)
@@ -71,14 +70,12 @@
  # define CONFIG_SONAR_SOURCE SONAR_SOURCE_ANALOG_PIN
  # define MAGNETOMETER ENABLED
  # define OPTFLOW DISABLED
- # define MAIN_LOOP_RATE    100
 #elif CONFIG_HAL_BOARD == HAL_BOARD_PX4
  # define CONFIG_IMU_TYPE   CONFIG_IMU_PX4
  # define CONFIG_BARO       AP_BARO_PX4
  # define CONFIG_SONAR_SOURCE SONAR_SOURCE_ANALOG_PIN
  # define MAGNETOMETER ENABLED
  # define OPTFLOW DISABLED
- # define MAIN_LOOP_RATE    400
 #elif CONFIG_HAL_BOARD == HAL_BOARD_FLYMAPLE
  # define CONFIG_IMU_TYPE CONFIG_IMU_FLYMAPLE
  # define CONFIG_BARO AP_BARO_BMP085
@@ -87,7 +84,6 @@
  # define MAGNETOMETER ENABLED
  # define CONFIG_SONAR_SOURCE SONAR_SOURCE_ANALOG_PIN
  # define OPTFLOW DISABLED
- # define MAIN_LOOP_RATE    400
 #elif CONFIG_HAL_BOARD == HAL_BOARD_LINUX
  # define CONFIG_IMU_TYPE CONFIG_IMU_L3G4200D
  # define CONFIG_BARO AP_BARO_BMP085
@@ -96,20 +92,20 @@
  # define MAGNETOMETER ENABLED
  # define CONFIG_SONAR_SOURCE SONAR_SOURCE_ANALOG_PIN
  # define OPTFLOW DISABLED
- # define MAIN_LOOP_RATE    400
 #elif CONFIG_HAL_BOARD == HAL_BOARD_VRBRAIN
  # define CONFIG_IMU_TYPE   CONFIG_IMU_VRBRAIN
  # define CONFIG_BARO       AP_BARO_VRBRAIN
  # define CONFIG_SONAR_SOURCE SONAR_SOURCE_ANALOG_PIN
  # define MAGNETOMETER ENABLED
  # define OPTFLOW DISABLED
- # define MAIN_LOOP_RATE    400
 #endif
 
-#if MAIN_LOOP_RATE == 400
+#if HAL_CPU_CLASS >= HAL_CPU_CLASS_75
+ # define MAIN_LOOP_RATE    400
  # define MAIN_LOOP_SECONDS 0.0025
  # define MAIN_LOOP_MICROS  2500
 #else
+ # define MAIN_LOOP_RATE    100
  # define MAIN_LOOP_SECONDS 0.01
  # define MAIN_LOOP_MICROS  10000
 #endif