Answer
If the kinetic energies are the same, the smaller-mass Ping-Pong ball has greater speed than the golf ball.
Work Step by Step
$$\frac{1}{2}m_{small} V_{big}^{2} = \frac{1}{2}M_{big} v_{small}^{2}$$
The same statement can be made for gas molecules that possess the same average KE; lighter ones move faster (on average) than massive ones.