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#21
Your running 1280 resolution with a 512mb graphics card and I would look there before moving on.
Try setting your resolution down to 1024 reboot and see if you still have lag. If you do not then you will know where the issue is for sure.
I believe that this may be the issue because graphics cards start to get stressed as the resolution is increased and not necessarily how graphics intensive something is.
Basically if your gaming at 800x600 you can crank all the settings to max even in some of the most intense games however at a higher resolution you need to start scaling back your settings so that the card can handle rendering them at such high resolution.
Since aero is very graphics heavy I would imagine you have the same problem. The higher the resolution the harder it taxes your card. And with only 512mb of vram on the card this could very well be your problem.
So give my suggestion a try and see what happens. If this is not the issue then we can look at other possibilities.