First, the preview architecture in Develop is unique to all other modules and the most accurate preview of the data. You should always view previews there and elsewhere at 1:1 or greater and when comparing, use the same zoom for each.
It is normal to see slight differences at 1:1 but if really excessive, the first thing to try is to disable GPU in preferences; better? If not, you might have a corrupted display profile. Recalibrate the display or whatever you usually do to create a display profile. When given the option to build this profile, pick Version 2 (not V4) and Matrix not LUT.
