I play Wars mostly at very low. I haven't noticed anything really disappearing when I switch between different graphic levels. All main objects seem to stay where they are. It looks to mostly affect textures, physics, and lighting. So all playing at very low does is signifigantly up your FPS.

Now, CE3, I don't know about.

This is why CE2 takes so much power, they made it well.

I have found that bad FPS translates to a poor multiplayer experiences when playing twitch games. Some is expected but I remember BF on the computer was horribly unbalanced against players with better rigs. Command & Conquer was the same way. By having an awesome system it made syncing and pinging much more difficult. I would experience lag while my computer slowed down for the opponent. It was annoying

For the people who wonder, how is FC2 running so well in every platform; the answer is this: In fact, the game hasn't the whole world loaded all the same time; it loads the map partially in "sectors", that are slightly bigger than the map editor's map size. XBOX loads 4 sectors/time, the PS3 loads 6. PC in low ambient settings loads 4, mediums 6, high 8... This is just a way to optimize them. Loading more than 6 sectors/time is not even needed. You can't see more than 6 sectors each time, without glitching. (Just know this as i have modded the game a lot, the files tell me a lot, i tell the files a lot.)