I just came back from an apple store, there's no option on display settings to lower the res to exactly 1440x900 on a 15" hi res model, only options I saw were some werid 14## x ### (stretch / no stretch) option, none of them look as crisp as on the low res model. I asked a Genius about this and they said they don't know why either... It's the same aspect ratio, why hi res model can't lower to exactly to the 1440x900? Driver issue??
It's got nothing to do with drivers, it's a trait that is inherent to ALL lcd monitors, it's a characteristic that's inherent to the way that lcd screens create an image. For technical reasons that I won't go into here (you can google it if you're interested) crt monitors can look great at many different resolutions, but lcd screens will only ever look good at their "native" resolution, where 1 pixel that the computer wants to display correlates with exactly one pixel of a spot of light that the lcd monitor is able to turn on or off.