I ran this comparison test again.  This time please see before and after for both Photoshop CC 2017 and Photo beta 4.  I had to manually adjust to get them both at 600% magnification, which, to be fair, is really nitpicking at this magnification.  But still there is a very slight artifacting that these quadrilles are contributing to - otherwise Photo Beta 4 is a dramatic improvement over previous versions of Photo.