CRM 2015 On Premise- Slow for regular users, fast for Admin

Hii,

We are using MS dynamics CRM 2015 om premise version. While investigating the slow issues for users, we have noticed  if regular users are given admini privilege then performance is much much better. Before admin privileges; to open a task it takes 4 seconds, with admin rights its roughly 1sec. 

Any suggestions to fix it? 

Thanks.