HANA - CE Functions vs. SQL Performance

Hello,

I am looking for a great example where the Calculation Engine of SAP HANA is faster than a native SQL command.

Currently I tried to join/calculate some big datasets (~few million records) with CE Functions and in native SQL (select a,b, sum(c) from tab1 inner join tab2...)

-> the commands are almost equally executed

Can you provide me any example? (e.g. SQL takes 5 seconds, Proc with CE Functions takes only 1 second) 

Thanks