Ultrawide 4k or 5k for MBP 15inch 2015 DG

[WujoFefer]

HI everyone
I have MBP15 from 2015 with radeon m370x and I want to buy ultrawide display.
Two options:
-For now LG 38CU99-W (38 inch 3840x1600)
-Or wait for LG 34WK95U (34 inch 5120x2160)

Is it possible to run one almost 5k60Hz display by my MBP15?
I'm developer and I don't want to change MBP for newer model only for screen without 32GB memory.

 

[Fishrrman]

I could be wrong, but I don't believe a 2015 MacBook has the video capabilities to support 5k on any display...

 

[ZapNZs]

I am far from an expert on displays, so someone please correct me if I am wrong?

To my understanding, the 2015 MBP will work with a 5k display like the LG UltraFine, but it will run at 4k because of bandwidth limitations. With the 2016-2017 MBP, when running a 5k display there are two DisplayPort 1.2a streams multiplexed via the Thunderbolt 3 cable because a single DP 1.2 stream is insufficient for 5k (IIRC a single 4k display at 60hz fully occupies all of the bandwidth of a single DP 1.2 stream.)

The forthcoming LG has a lower vertical resolution than the UltraFine, which I assume means a somewhat lower bandwidth. However, it seems that this would still not be enough for 5k60hz?