AndreasHelke - is mostly correct and thank you for the input.
This is what happened.
The meter performance is a combination of our code running in the flashplayer on your machine.
We can rewrite/optimize the code which will make the meter better or worse for everyone. But once the code is live, we have no way on a daily or hourly basis, or a per person basis influence the performance of the meter. Once the code is live, all the variations are due to your machine, operating system and flash player. Even on the same machine if you have 3 apps open vs 1, or if you are streaming music, or you have the WGT.com site in the background... these will all affect the meter.
With this last release in response to meter complaints, we made some major changes to the way the game renders which includes the meter (You will see that the frame rate has changed). This investment was made in direct response to people who say we never do anything to make the basic game better.
Unfortunately the changes had a negative affect on certain browser and flash player version combinations. We then worked extra hard to fix those compatibility issues while maintaining the new rendering functions we deployed.
The end result as of 7pm last night is that we have the new rendering and it is now compatible with almost all customers.
Thanks for your patience and I hope things are better for you on WGT.