I overclocked my TI-89 Titanium from ~12.3 MHz to more than 25, now I can see 4-level grayscale dithered graphics at 5 SPF

Overclocking was done using the “pencil” method: https://www.cemetech.net/forum/viewtopic.php?t=17640&start=0

The graphics shown in the video were generated by ClosedGL 13.37: https://www.ticalc.org/archives/files/fileinfo/361/36173.html

Finally, the clock frequency measurement program is actually one of my own programs. https://www.cemetech.net/downloads/files/2595/x3389