No, it is not. I bought this cable and had to find out the following:
This cable is basically not suitable for connecting a monitor directly to the PC/graphics card.
This is because pin 20 of the display port cable is connected. This pin supplies the PC/graphics card with power from the monitor, which, however, according to the interface definition, must not happen with direct connection of monitor to PC. This power supply at pin 20 is intended for intermediate devices, such as repeaters, etc.
Source:
https://www.necdisplay.com/documents...
If the pin 20 connection could be cut, the cable could certainly be G-Sync compatible.