Slow operation of ST7796s SPI

PB - stm32

// These are 'flexible' lines that can be changed
//#define TFT_CS 10
//#define TFT_DC 9
//#define TFT_RST 8 // RST can be set to -1 if you tie it to Arduino's reset

#define TFT_CS PB3
#define TFT_DC PB10
#define TFT_RST PB12

// Use hardware SPI (on Uno, #13, #12, #11) and the above for CS/DC
Adafruit_ST7796S_kbv tft = Adafruit_ST7796S_kbv(TFT_CS, TFT_DC, TFT_RST);