Hi
Thanks a lot for doing performance measures with U8g2.
Regarding the _1_ vs. _F_ You must not use sendBuffer and clearBuffer together with the _1_ constructor.
sendBuffer and clearBuffer are only allowed for _F_ constructors.
The differences are described here: setup_tutorial · olikraus/u8g2 Wiki · GitHub
Basically you trade RAM vs. Speed, so the _1_ constructor will definitly be slower than the _F_ variant if used correctly.
Regarding your measurement: I tried hard to understand your code, but I am unable to follow, how you derive the frame rate.
I do not have an up to date measue, but I will check the current speed with u8g2.
Here is another link on this topic: http://www.best-microcontroller-projects.com/ssd1306.html
Oliver