I replaced the PCB with the powerbooster with my old non-boosted one, and removed the heatsink. Here is some pictures of the circuitry powering Fan1 3pin;
There seems to be brown marks around the FET and some sort of solder-like substance coming out between the FET and the PCB...
Also in the picture the 2 resistors increasing channel 1 power are clealy visible, so there is no doubt wether this is the factory-modified power-boosted version.