Overclock not working with Master System

[pegonma]

I have been trying to play Sonic 1 and Sonic 2 (8bit) on the Master System, and as usual with precise emulation, there are many slow-downs in the game due to the limitations of the Master System hardware (just try the first level of one of those games and you'll see). However, I believe using the "68k overclock" option should get rid of these slowdowns, but it does not change anything.

If I'm not wrong, the Master System does not have a 68k processor but only Z80, perhaps this is the reason?

(The emulator Genesis Plus GX does this well, but scrolling is not smooth there with Sonic 2 because of Audio Sync it seems).