@eckaji I am running at 1.45ghz with on the CPU. I've pushed it all the way to 1.6ghz but that would usually end up counter productive as it would heat throttle. I'm using a Flirc case.
For GPU I'm running at 500mhz vs the stock 400. If I go past that I will get frame drops and hick ups even with good heat and frame rate. My RAM has a similar +100mhz on it, honestly I think the RAM overclock is the most beneficial. You can't crank it up too high, though, as RAM OC can get unstable in a hurry.
I'm happy with my 3B+ and will use it for hundreds of gaming hours. However, there is no real performance boost with it over even a mildly overclockes 3b in my experience.
On the positive side, the WiFi is far superior and my Buffalo controllers no longer give ghost inputs like they did on the 3B. This makes me think that the 3B had some USB power supply issues.