iMac 5k with Unreal?

Hello there Unreal Community!
I am thinking about getting an iMac with Retina 5K display.

The specs would be as follows:
4.0GHz Quad-core Intel Core i7, Turbo Boost up to 4.4GHz
32GB 1600MHz DDR3 SDRAM - 4x8GB
3TB Fusion Drive
AMD Radeon R9 M295X 4GB GDDR5

Would this computer be able to handle UE4 flawlessly?
Would it be able to spawn in assets/move models without lag and would it rebuild lighting at a good speed?

I’m sorry if I made this thread in the wrong forum category.

It would if they were to use the Metal API for OSX in the editors, etc.

At WWDC they announced it was ready to download. I don’t see any sign of it.

In fact the latest build (4.8) doesn’t even function on OSX 10.11.

The current/newest version of OSX is 10.10.3…

Any Mac users that have any info/advice?