This paper investigates the effects of top fin width scaling (Wtop = 4, 6, 8 nm) of p-and n-type 10-nm FinFET on the electrical performance of the device, specifically optimized for low performance (LP) and high performance (Hp) devices. The work also studies the correlation of the metal work function to the device performance. It is observed that the transfer characteristics shown increased drain current in linear region towards increased Wtop for both p- and n-FinFET. The threshold voltage is shifted to the right for p-FinFET as the work function is increased. Oppositely for n-FinFET, they shifted to the left as the work function reduced. The Ion/Ioff ratio reduced as width increase. The observations on Ion/Ioff ratio for low performance device show the magnitude drops to 63% and 82% in n-FinFET and p-FinFET, respectively when the fin width is changed from 4 nm to 8 nm.