Resolve 12.5 freeze. Hard shut down required.

My Resolve Studio 12.5 constantly freezes to a point where I can not quit out of it and need to do a hard reset.

The footage is Ursa 4.6k - anywhere form 1080 - 2k
Even without NR and just a basic primary grade it will freeze.

The compter specs are:
I have a mac pro (late 2013)
3.5 GHz 6-Core Intel Xeon E5
16 GB 1866 MHz DDR3 ECC
AMD FirePro D500 3072 MB

I've had a suggestion of purchasing Nvida Geforce GTX 1080.

Just wondering if anyone has tried this or has any suggestions? Any help would be amazing..

Cheers