If thats without delidding at about stock 1.2v thats a very good temp yeah. Dunno why your temps are jumping around, from the thermal past not been spread properly i normally find one or 2 cores is a lot hotter than the others, rather than jumping temps.
It's not so bad now, the temps are only jumping around 2-3 degrees but as of currently with a 1080p Twitch stream and a few other tabs I have 24 degrees on the first core, 25-27 on the second, 24-26 on the third, 23-26 on the fourth, and 26-30 on the package. They are sometimes jumping up to around 35 though for about half a second, not sure why though?