Many pages vs one page

Hi giorgiokatr,

I would like to continue with Anonymous's suggestion but with a little bit difference that you need to clarify that the lagging is coming from rendering layer or data transfering layer.

• Cause render layer:
  • if the root cause is render layer of charts control or PBI service that could not handle your amount of data, we could ask some staffs to check service again or raise ticket  to MS for improvement.
  • Check and optimize your calculated measure/column 
• if the root cause is from data transfering, we need to clarify:
  
  • With Importing mode, there will be a lagging or short delay each refreshing time cause your data is huge. And you don't need to care about limitation of 10GB, cause as my observation, we could add more space for tenant users by buying more tetnants and shift their space to your account. but you need spend time to optimize your data model and DAX expression. Please refer this topic and another topic of sqlbi.com cause i found there some good optimize topics in there (refer topic for optimize tabular model same as for power bi) 
  • With Direct Query, you need to check your server side again cause the response time will depend on computing power of your server side or your index of db.

And the last note that we should optimize whenever we can, don't wait to huge or bigdata. 

Hope you provide more information as above description so we could help you in specific case.