ST7920 has artifacts on ESP32-S3

[gaznoziy]

Lib version: 2.35.30

I'm using ESP32-S3-Pico dev board from Waveshare and trying to connect ST7920 via default HW SPI.
Default SPI pins defined for this board are:

static const uint8_t SS = 10;
static const uint8_t MOSI = 11;
static const uint8_t MISO = 13;
static const uint8_t SCK = 12;

Using this constructor U8G2_ST7920_128X64_F_HW_SPI u8g2(U8G2_R0, 10); leads to appearing artifacts on the LCD. After some tries to make it work I've figured out that manually setting u8g2->setBusClock(800000); resolves an issue. Clocks that are higher than 800000 hz are breaking display.

Previously I've used the same LCD with NodeMcu ESP8266 and with this constructor U8G2_ST7920_128X64_F_HW_SPI u8g2(U8G2_R0, D8); everything worked fine without setting bus clock. Just made some tests with ESP8266 again and it seems that artifacts appear on clocks set more that 1.1MHz.

I'm fine with using it at 800000 hz, but just curious why can this happen on ESP32?

Also hope this helps someone struggling with the same issue.