I chose Sapphire brand for this topic besides being one of the most favorable/popular gpu manufacturers for amd particularly because it is the one of the manufacturers I'm interested in buying Vega cards from in the near future, but I think it probably applies to all current Vega manufacturers (Sapphire, Gigabyte, MSI, Asus...etc.) since they all use(are selling atm) reference AMD's blower cooling design for their Vega cards at the time of writing this topic.

According to http://www.sapphiretech.com/productdetial.asp?pid=AE163547-6889-4073-BBF6-9DB2C45BB233&lang=eng
under the "specifications" button it is clearly stated that
RX Vega 64 features dual ball bearing fan solution, and that's alright.

But,
nothing is said for RX Vega 56!

It is only stated that it's a blower cooler.

What bearing fan solution are they using for Vega 56? I fear it might be cheaper sleeve bearing fan solution but of course I can't know this for sure because Sapphire didn't answer me yet and I didn't find any source elsewhere. and I doubt it is two ball bearing because if it is then why wouldn't you contain it in the datasheet specs on your own web page? of course I could be wrong, just my own assumptions here...

Anyways,
if any of you guys know for sure let us know here.

I tried and this info is hard to google since most of the search results either direct you to reviews or datasheets which do not contain this particular little piece of info, seems like people don't care about fan efficiency or I just suck at googling

Thank you!