Question for Ivao online flyers

I have raised this subject on the Ivao forums but as of today I got no answer.

Can someome explain to me how the Ivap refresh interval in the Online Traffic-Performance Tuning section of Ivap Configuration Tool affects performance ? In particular:

1) In theory the higher the refresh interval the smoother is the movement of the online traffic, but CPU load is also higher: is this correct ?

2) The default refresh interval is 20 Hz. Should it be changed to match with monitor refresh rate (i.e. 60 hz or 30 if using the 1/2 Vsync tweak) to have better results or are they completely unrelated parameters ?
 

Anyone able to shed some light on this subject ?

Thanks