PliotronX was mostly right. A BNC->15pin cable will not increase image quality because the you're "bottlenecked" by the 15pin end. However it is incorrect to say that any noticable difference is placebo effect, because the BNC->15pin cable itself can still provides better data integrity than the some mid/low-end 15pin-15pin cables(but manufacturers like Sony and Samsung usually dont bundle low quality cables with high-end monitors), but if you use high density, high quality 15pin-15pin cables, BNC will have virtually no advantage. The other thing is, Windows work just fine with the non-PnP compliant BNC inputs, it will not go crazy.