When was our I9000 th fastest (which ROM)?

I am enjoying different mods and new devlopments, but using yesterday evening S4 mini, I asked myself this question:
The Moment I hit an Icon (.z.B.) Whatsapp, ´the window Comes up and I have tried it on my I9000 and it takes ca. 5-10 sec.)

Obiously, newer Versions have aditional functons, but:

Which Firmware or Developer Version since I9000 came to market was the fastest, in your opinion, "FOR SIMPLE USE: TEXTING; WHATSAPP; MAPS, LIVESCORES; ETC.???

Thanks for all your comments.

Pavana