RX 570 Fans never seem to kick up in my Hackintosh?

Hi - I recently picked up a Powercolor RX570 4gb for my Hackintosh.

It works great, installed the evergreen script from Multibeast and it boots great etc, FCPX is running like a dream.

I opened my case the other day to switch an SSD after shutdown and noticed the GPU really felt hot to the touch, not just warm.

The fans are running constantly, but only at like an idle speed - they never seem to kick up, the only time they have done is sometimes when I boot the system. Even when I spend 3/4 hours editing 4K footage it never seems to kick the fans up.

Is this normal? Should I only expect the GPU to really need the fans to kick up during a game or something?

It doesn't even kick up during something line Cinebench etc.

Spec: i7-6700k Gigabyte Z170X-UD3 32gb Corsair Vengence RAM Samsung 850 Evo SSD

Should I be worried? Unfortunately I can't seem to get HWsensors working for this card...