A Very Strange Performance Issue

Hello all,

The measure called Final Measure below works very slowly on visuals we use with "Drill-Down" and "Matrix". In the performance results we make in PowerBI (visuals used with similar size measures), it can reach 25 seconds at some points. 

My Connection type is Live Connection trough Analysis Services

I have shared Final Measure and other important measures that make up it. I need to imrpove the performance results of the querys

Because it has 1.5Million Rows of Data and it gives the memory limit errors.

Final Measure:=IF (SELECTEDVALUE ( Dates[Is Month] ) = TRUE ()
 || [Selected Metric] = "CC",IF (SELECTEDVALUE ( Customer[Cust:Key] ) <> "44/05/AA/2208909",IF (ISFILTERED ( Category[Category Name] ) = TRUE (),
            [Sub Measure 1],
            [Sub Measure 1] 
               - CALCULATE (                    
[Sub Measure 1],                    
Category[Category Name] = "X Group"                
)        
),        
[Similar to Sub Measure 1]    
),    
[Similar to Sub Measure 1])

Sub Measure 1 :=SWITCH (TRUE (),    
[Selected Metric] = "Actual",IF (            
[Search Filtered Business] = TRUE (),            
[Sub Measure 2]                
+ CALCULATE (                    
[Sub Measure 2],                    
Category[Category Name] = "X Group",ALL ( Category )               
 ),           
 [Sub Measure 2]       
 ),    
[Selected Metric] = "CC",IF (            
[Search Filtered Business] = TRUE (),           
 [Similar to Sub Measure 2]               
 + CALCULATE (                   
 [Similar to Sub Measure 2],                   
 Category[Category Name] = "X Group",ALL ( Category )               
 ),
           
 [Similar to Sub Measure 2]       
 ),    
[Selected Metric] = "Volume",IF (           
 [Search Filtered Business] = TRUE (),           
 [Similar to Sub Measure 2]                
+ CALCULATE (                   
 [Similar to Sub Measure 2],                   
 Category[Category Name] = "X Group",ALL ( Category )               
 ),            
[Similar to Sub Measure 2]       
 ),BLANK ())

Sub Measure 2:= SWITCH(TRUE(),    
[Selected Metric] = "YTD",TOTALYTD(SUM(Sales_Summary[Actual]),'Dates'[Date])   
 ,    
[Selected Metric] = "MTD",TOTALMTD(SUM(Sales_Summary[Actual]),'Dates'[Date])   
 ,BLANK())

İts very Critical and it hapenned after I used this 3 daxes. Let me know if you have any questions to solve this

Thank you all for your time.