iejun:
Is the Uno capable handling the data ?
Yes
iejun:
Am i using too heavy load servo's ?
Yes
iejun:
Is it because i didnt use a capacitator ?
No
A servo is pretty power hungry, it can draw 1A with ease. And a stall current of 2A isn't even weird for a small servo. According to this your MG995 has a stall current of 1,5A. So for 16 servo's you're going to need a beefy beefy power supply if you want to control them at the same time. A cap isn't going to fix that... It may need a little if you're on the edge but with 16 servo's on a 2A supply you're wayyyyyyyy over that edge 