Some photo previews are unsharp when shown on my screen by DxO PL, although other RAW editors show them correctly. This is already so before any adjustments are made. I have attached 2 screenshots. The first is a section from a 100% preview in DxO PL, the second shows the same section in Capture NX-D. The render is from a 24,78 megapixel raw file taken with a Nikon DSLR. My screen is a 24" 2560x1440 pixel screen. No adjustments are made.
This or similar problems seem to have been reported before in this forum, but no posting seems to be clear enough to get an adequate answer. I hope this helps.