Power BI service Refresh failure

1) You're not the only workload on that capacity. Performance varies based on workload, time of day, seasonality etc

2) You need to distinguish between retries and full failures.  Your example doesn't count as it eventually succeeded. It has to completely fail all four tries  four times before the schedule is disabled.

Having said that - whatever you do to speed up the refresh is absolutely helping. Remember there is a hard limit (5 hours in Power BI service, but can be shorter in the data source) and you want to stay well under that.

Hi hoosha_11 

1) In a non Premium capacity workspace, this late is a shared capacity (Pro license), meaning not only the RAM is lower than in a premium capacity but also it is not dedicated to the workspace. 

2) Not sure that after 4 times of failed refresh Power BI disable it, but you can set an email notification when it happens.