gpu Memory Statistics

Hi folks!

Quick question that I cannot find answer for it anywhere:

how to see some precise info about my render memory when rendering gpu cuda? (2.74)

I see this bar on top with frame, time, memory and peak but I want to know how much exactly weight my geometry etc

i know it is an option SPACE > Memory Statistics but it does nothing. Please advice how to move on with that matter.

Thanks in advance,