Which one is it ??? Are they selling good in EU (according to Gibbo) or they are too expensive ???
Perhaps EU got more volume or AMD didnt expected that much interest from the consumers in US. Or, from now on most of the chips are going for the custom cards and reference models volume will decrease.
I would say it depends on a EU country. Remember EU is not single state and completly unified market either (not to an extent US is).
I would not be surprised if it sold very well i.e. in UK while at the same time sell moderately or poorly i.e. in Italy or somewhere else.
So in Poland it is not selling "like hot cakes" because price in Poland is jacked up 200 zł (~50 euro) over official Polish MSRP set by AMD in all retailers and there is no problem finding RX 480 in stock. All popular stores + Allegro (Polish version of Ebay) have them available and in plenty of numbers.
Some of most popular online shops say that this is due to GPU manufacturers (i.e. Sapphire, Gigabyte, etc) selling them for high prices and refusing an official AMD MSRP price for now.
Obviously customers don't like that. It would sell much better if they would be in official MSRP (1170 zł set by AMD) instead of what price is on the market everywhere (1349 zł in stores).
Also only 8GB versions, there is ZERO 4GB versions in Polish stores. I did not even saw it listed anywhere.