1080Ti - second 4K Monitor refresh @30 not 60?

[prowlmedia]

So anyone have any idea why my second Phillips 4K monitor referesh is low PHL BDM3275

Monitor does work at 60 when it's on it's own.
Cable checked and swapped over - So they are both 4k / 60 compatible.


Chipset Model: NVIDIA GeForce GTX 1080 Ti
Type: GPU
Bus: PCIe
Slot: PCI Slot 0
PCIe Lane Width: x16
VRAM (Total): 11 GB
Vendor: NVIDIA (0x10de)
Device ID: 0x1b06
Revision ID: 0x00a1
ROM Revision: VBIOS 86.02.39.00.9d
Metal: Supported, feature set macOS GPUFamily1 v3
Displays:
PHL BDM3275:
Resolution: 3840 x 2160 @ 30 Hz
Framebuffer Depth: 24-Bit Color (ARGB8888)
Main Display: Yes
Mirror: Off
Online: Yes
Rotation: Supported
Automatically Adjust Brightness: No
Connection Type: DisplayPort
Television: Yes
PHL BDM3275:
Resolution: 3840 x 2160 @ 60 Hz
Framebuffer Depth: 24-Bit Color (ARGB8888)
Mirror: Off
Online: Yes
Rotation: Supported
Automatically Adjust Brightness: No
Connection Type: DisplayPort
Television: Yes

 

[prowlmedia]

Could it be the Nvidia drivers?