No if you limit yourself with a 7.8 sail.
Yes if you take a much bigger sail and fin : you'll gain 4 knots in the lower wind range by swapping a 7.8 sail + 44 cm fin combo with an 11 m2 sail + 55 cm fin combo.
I'm using the 2012 iSonic 117 wide since a year with 7.7/8.6/11 m2 sails and it's the perfect light wind gear for my 65 kg. No need for anything larger. In stronger wind, I switch to iSonic 53 speed with 7.7 & 6.6 m2 sail.