A. If you are getting lag with Flash content & streaming movies, you can do two things that should provide a huge improvement to performance (I do not know if the same thing can be done with 3G):

1. Adjust the cache to 40mb in the browser options / settings
2. If you are using wifi, go to your connection and edit it using the advanced options. Change power setting to the medium option. I was unable to keep a steady video stream or play the larger Flash games until I adjusted this setting. This is in spite of having my N900 in the same room as the router- seems the default setting may be too conservative for some. I am not noticing much more power consumption, but will need a few days to confirm.

B. Flash games with minimum overhead:

1. Save Flash games to a folder of your choice on the N900
2. Use the file manager and go to where you saved the game
3. Launch the game
a. You can adjust the size with volume buttons
b. Hold down on the screen until the Flash menu opens up
c. Adjust the quality setting to low - you will not notice a quality difference on a 3.5" screen, but will notice the performance increase
d. Have fun playing a zillion games