The cooler is the same on all cards, yet a huge variance. Its simply because the chips electrical properties got a huge variance as well. And AMD already showed how little faith they got in their product in this case with the base/boost delta. A baseclock may I add, that AMD do not want to list anywhere in their material.
So no, the chip is not fine.
You know what else has variance? Coolers. Both the cooler itself (e.g. the base) as well as the TIM.
Combine a small natural variance in chips with a natural variance in coolers, and you get an fairly high variance.
Add in an individual's case variance (airflow, other components etc) and now you have 3 or 4 factors which combine to mess things up.
Slap on a good enough cooler that those variances no longer matter, and it's all fine.
If all the chips were perfect, then sure, the cooler might not matter, but if all the coolers were better, the chip variance wouldn't matter either. And it's quite easy to fix the cooler, as identified by the people who have put on a different cooler.