The swing meter plays on your computer.
A major factor that determines if the swing meter is smooth or not is how busy your computer's CPU is during the down swing.
So many of us use Windows Task Manager to look at the performance of our computer's CPU as we pause at the top of the back swing. We start the downswing when the CPU performance reaches it's lowest ebb. Some people just pause at the top of the back swing for a 3 or 4 count as a way to give the computer's CPU some time to settle down to a lower level of activity. By looking at the CPU performance it's readily apparent that CPU performance pretty much always settles down after a few second pause at the top of the back swing.
Other things that can affect the swing meter is having a bunch of web sites listed in the Flash Player Web Site Privacy Panel (you want it to be empty) and having a lot of old temporary Internet files stored on your computer. You should also clear your browser's cache before you play.
It is best if the game client tab is the only tab open on your computer and you want to minimize how many applications and processes are running in the background on your computer.
For more detailsl - Optimizing Your WGT Experience