DAX performance optimization

Hello Community,

It will be a long post, sorry guys but I'm really in need of help.

I have a DAX for ranking and segmenting users based on consumption but it has big performance issues. It takes way more than a minute - or it times out - to calculate it on a monthly date range for example.

Below I'll try to add all the details you might need. 

Model:
basic calendar table: has a relationship with stream on Date-date
stream table: contains consumption on a daily-user-content-platform level so pretty detailed and huge: about 52m rows for 8 months period

and here is the DAX I use:

the goal is to categorize the users based on their consumption and to tel for instance that the "heavy" category which contains the top 25% of the users in the given time period is responsible for the 70% of the consumption

The idea of the solution comes from the EnterpriseDNA  youtube channel.

//simple sum of views:
Net Stream views = SUM(stream[net_stream_views])

//the rank based on views where I rank the users if they had at least 1 view in the given period:
ViewRank = IF(ISBLANK( [Net Stream views]),BLANK(),
        RANKX(
            FILTER(ALL(Viewers2),NOT( ISBLANK([Net Stream views] ) ) ),[Net Stream views],,DESC,Skip))

//the segmentation where I'm trying to iterate throug the viewers and categorize them 
//to the categories located in the UserSegments table based on the useres rank
Segmentation = 
VAR RankingDimension = VALUES( Viewers2[gigya_uid] )
VAR TotalCustomers = CALCULATE(COUNTROWS(Viewers2), FILTER( ALL(Viewers2[gigya_uid] ),[Net Stream views] > 0 ))

RETURN
CALCULATE( [Net Stream views],
    FILTER( RankingDimension,
        COUNTROWS(
            FILTER( UserSegment,
                [ViewRank] > TotalCustomers * UserSegment[Low] 
                && [ViewRank] <= TotalCustomers * UserSegment[High] ) ) > 0 ) )

what I'm trying to get is something like this for example:

Is it possible to optimize this solution to boost performance or to solve it a different way to keep it dynamic?

If you need any other detail don't hesitate to ask. :)

Thanks for your time in advance.

Bests,
Barna