WSJT-X V1.6 decode sensitivity

For many months I had been using V4 of the dedicated WSPR software After about a day of use I do not think WSJT-X V1.6 has demonstrably better sensitivity.  On spots of EA5DOM and PA3ABK/2 the S/N of decodes seems very similar in S/N terms. It is possible this not widely release version decoded at a similar level to WSJT-X V1.6. Certainly the QSB makes making a clear picture far from easy. What I mean is the signals vary far more with fades than the difference in sensitivity between packages. At the moment I am not using the preamp.