How rate of Reading SD-CARD works ?

Other Hardware Storage
3

Sorry about my english !

For rate I mean the duration of function SD.open()

File current_image;
File next_image;

void set_spi_for_sdcard(void) {
//	SPI.end();
	SPI.begin();
	SPI.setDataMode(SPI_MODE0);
	SPI.setBitOrder(MSBFIRST);
	SPI.setClockDivider(SPI_CLOCK_DIV128);
}

void abre_imagem(const char *nome){
  
       current_image.close();
       current_image = next_image;
       next_image = SD.open(nome);
}

and the char "nome" is something like "1.144", "2.144", "3.144", etc...

I used the funciont millis() to get the duration of functin SD.open() and for each image, takes different time !

I have to increase that function !