Adafruit OLED driver vs u8GLIB

Kolynskij:
#include "U8glib.h"

void loop(void) {

cls();

//send_str="Nova1"; // try and write the image using a string to
//draw(send_str); // reference it. Fail!

draw();
// rebuild the picture after some delay
delay(1000);
}

The cls() call is not required. The draw loop will erase the picture for you.

Another problem is this: The old u8glib does not select fastest possible speed for the target display. So I guess u8g2 will be faster here.

Just for completion: U8g2 includes a text only sub-library called "u8x8". It also does not require any screen buffer, but restricts text output to 8x8, 8x16 and 16x16 pixel.

Oliver