Help with CCC presets completly Bugged !

Your cards should automatically throttle themselves. There's usually three performance states. Idle, 2d, and 3d.

So at idle the card would be at lets say 250MHz core and 150 MHz memory (performance state 0).
2D clocks are usually used for media type applications and are clocked at 500MHz core, 1200MHz memory. (performance state 1)
Then the 3D clocks are your peak power which should be 800MHz and 1200MHz memory (performance state 2).

At any rate, download MSI afterburner and in the settings menu click on the "Monitoring" tab, then in the section labeled "Active Hardware monitoring graphs" scroll down to "core clock" and "memory clock", click on one of them to highlight it, then down towards the bottom of the window click on "show in On0Screen display". Make sure you do that for both the core and the memory clocks.

Then launch a game and see if the settings you tried changing in Overdrive took. It may just be the case that this flicker that you see is simply the card just reverting back to its idle state clocks.

Do that and report back.