Pi 3 b+ has no default overclock options. It’s just a fun project to see if I can run same romset as my arcade machine. As it stands, the pi is already better than these retro consoles (my opinion) because it has composite out. I don’t expect it to be perfect. I don’t even play video games. Just like the hobby. Arcade reminds me of time with my father as a kid.
I am not sure if I am picking up what you're putting down correctly, but yes, you can overclock the Pi3+... I'm running mine at 1475mhz but more importantly I'm overclocking the core/gpu, etc to 550mhz.
Also, I agree that you should never use the supplied sticky crap with any heatsink... I have a tube of thermal epoxy here for just such cases. Prior to the HSF I could only overclock to 1450 stable... with it I'm at 1475 rock stable... 1485 will run for hours but did crash once so I pulled back a hair. Sure... 25mhz aint much, but it's something... and it's fun to tinker.
For the fan, I simply attached a 12v 40mm fan mounted via a PCB standoff blowing across the epoxied heatsink...
As for noise... it's nearly dead-quiet ... and when I close the control panel you can't hear it at all.
As for power consumption, my Pi is in an arcade cabinet and I'm pulling the 12v from the much much overkill arcade power supply.
