Also, Windows 8 is the preferred OS for this Vdeo card, not sure whether earlier Oses will recognise the utilization if PCIe 3.0.
It might still be that the PSU is not providing adequate power despite requirements being met. Itmight be that you will need at least a 750 watt PSU so that adequate power is available for the fans, however all the reviews state that it does draw less power than lesser models.
Try playing a game or watching a movie and then see if the fans begin to spin. It might be that they are spinning but are very quiet and you can't hear them whirring.
Upon further research, it seems that Windows 8 is the only OS that initially supports PCIe 3.0 but there is a fix for Windows 7 -
I just think it same as some PSU fans profile (silence serries), if it still cold the fan will turn off (lower noise lever), if it getting hot then it will start spinning.... (they even make this as plus poin / marketing feature)
but it only guessing, try contacting HIS consumer support to make sure
don't worry too much with pcie ex 3.0 the diffrent is minimal and only (little) noticed in 7970/680 tier card...
all pci-ex 3.0 backward compatible with 2.0
edit: I would try using afterburner custom fan profile for testing, see if after manually set the fan profile it still had same symtom or it will work as the custom fan profile..
If it had same symtom then there is something wrong....