Can anybody explain anything about FSX engine rendering?

There are differences between FSX and FS9- if you change views, instead of gray textured items (buildings, aircraft etc) there are now 'ghosts' rendered that get covered with textures. The aircraft certainly have more polys and structures.Texturing on a 256mb card- Are there really THAT many megs of textures that FSX needs? As it is, I cringe at the thought on a 128mb card.