Macbook Pro, 13-inch, 2015, Intel graphics 6100. So I guess not. The 4K display is connected via displayport, and runs downscaled at 2560x1440.
OK, I would expect that setup to perform really well (like just a couple % CPU use in activity monitory). If you have a chance, can you send a sample[1] to support at realartists.com? I'd love to see what's taking all that time.