I'm curious, no one ever mentions whether they're playing in the browser window in full view mode or whether they're playing in the client window maximized. This shifts the Flash 'container' into a lower res and lower overhead mode.
I'm not talking about running the browser in full screen mode, that doesn't do it, you have to run the client window in full screen mode, you know you are when the graphics shift, lower res, looks a bit washed out. That will almost totally smooth out any meter chatter.
You also have to flip browsers, that's just the nature of the best. I used the Maxthon Beta that has a great rep, for some reason it sucks now. Opera was awesome for a while, now I'm back on Chrome. FF is always ass for me, no matter what.
And your hardware doesn't really matter all that much.. I'm playing on a T61 lenovo laptop with an Intel chipset... 965 I believe, not the 128 nvidia model. I rarely have meter issues. When I used my SolidWorks/Gaming rig, with SLi'd 560's? Nothing but friggin issues.. plus I was cabled right to the modem on a 25/15 cable connection. Now I'm on wifi running about 10/3 so ya... lol
If you want to see what's really going on within the client window, go create an adobe account, download Scout and run it, then open WGT, the client window and play. If you have a dual monitor setup this works much nicer as you can watch the various resources etc as they max out, dump, level off in memory etc....