UE4 don`t runs on MacPro 2008

Hello,

On my MacPro 2008 (iOS 10.11.6 ) I would like to operate UNREAL ENGINE 4.
Unfortunately, UE4 does not open.

Do you have a tip why that could be?
Are there certain settings to be made on the graphics card?
Is the Mac too old?

Hardware Overview:

Model Name: Mac Pro
Model Identifier: MacPro3,1
Processor Type: Quad-Core Intel Xeon
Processor speed: 2.8 GHz
Number of processors: 1
Total number of cores: 4
L2 cache: 12 MB
Memory: 12 GB
Bus speed: 1.6 GHz
Boot ROM Version: MP31.006C.B05
SMC version (system): 1.25f4
Serial number (system):
Hardware UUID:

NVIDIA GeForce GTX 680:

Chipset Model: NVIDIA GeForce GTX 680
Type: GPU
Bus: PCIe
Slot: Slot 1
PCIe lane width: x16
VRAM (total): 2048 MB
Manufacturer: NVIDIA (0x10en)
Device ID: 0x1180
Version ID: 0x00A2
ROM version: 3731

Thank you and best regards,

Are you receiving any error messages when trying to open UE4? Also, how much RAM does your system have?

No, there is any error message.
12 GB RAM are installed.
Thanks