Code execution time is very slow

Hello everyone, I have a core board of F401CCU6. In the first test, I lighted three rgb leds.

The interval time is 1000ms,.
but after I upload the program, the interval between the two colors is about 2000ms.
This is much slower than in my code.

  #include "Arduino.h"
  int red = 0; 
  int green = 1; 
  int blue = 2; 

  void setup()


  pinMode(red, OUTPUT);
  pinMode(green, OUTPUT);
  pinMode(blue, OUTPUT);

  void loop()

  digitalWrite(red, LOW); 


  digitalWrite(red, HIGH); 
  digitalWrite(green, LOW); 


  digitalWrite(green, HIGH); 
  digitalWrite(blue, LOW); 


  digitalWrite(blue, HIGH); 


Compilation results:

    Processing blackpill_f401cc (platform: ststm32; board: blackpill_f401cc; framework: arduino)
    Verbose mode can be enabled via `-v, --verbose` option
    PLATFORM: ST STM32 (12.0.0) > BlackPill F401CC
    HARDWARE: STM32F401CCU6 84MHz, 64KB RAM, 256KB Flash
    DEBUG: Current (blackmagic) External (blackmagic, cmsis-dap, jlink, stlink)
    - framework-arduinoststm32 4.10900.200819 (1.9.0) 
    - framework-cmsis 2.50501.200527 (5.5.1) 
    - toolchain-gccarmnoneeabi 1.90201.191206 (9.2.1)
    LDF: Library Dependency Finder ->
    LDF Modes: Finder ~ chain, Compatibility ~ soft
    Found 18 compatible libraries
    Scanning dependencies...
    No dependencies
    Building in release mode
    Compiling .pio/build/blackpill_f401cc/src/main.cpp.o
    Linking .pio/build/blackpill_f401cc/firmware.elf
    Building .pio/build/blackpill_f401cc/firmware.bin
    Checking size .pio/build/blackpill_f401cc/firmware.elf
    Advanced Memory Usage is available via "PlatformIO Home > Project Inspect"
    RAM:   [          ]   1.4% (used 892 bytes from 65536 bytes)
    Flash: [          ]   4.1% (used 10876 bytes from 262144 bytes)


What text is on the crystal or what does the board manifufacturer say the crystal frequency is? 25 MHz?

It could be wrong clock settings to a wrong final operating frequency of the chip.

Is the behavior the same with board = genericSTM32F401CC in the platformio.ini instead of blackpill_f401cc?

Hey,The crystal is 12mhz.
I also tried to set board = blackpill_f401cc, but the flashing time became faster, about 500ms apart

Can you please use the platformio.ini

platform = ststm32
board = genericSTM32F401CC
framework = arduino
build_flags = 
   -D HSE_VALUE=12000000U

and retry.

OK,thank your suggest.