FlatpanelsHD put together an interesting analysis of why Samsung's Galaxy Nexus' 4.65-inch, 1280x720 Super AMOLED screen probably isn't comparable to Apple's 326 ppi Retina Display despite having a pixel density of 315 ppi. The reason: PenTile technology.
FlatpanelsHD points out that the Super AMOLED display the Galaxy Nexus uses is founded on PenTile technology, which uses a two subpixels instead of three to theoretically cut down on power consumption (they call it a "shared subpixel"). Calculating out the total number of subpixels in the Galaxy Nexus and comparing it to the likes of the 800x480 Galaxy S II and the 960x640 iPhone 4, both of which use three subpixels in their displays, along with the 1200x800 Galaxy Note tablet (which uses the same PenTile tech), they found that Nexus display had the same number of subpixels, despite being an inch bigger.
"And if you calculate the real pixel density you will find that the Galaxy Nexus is actually closer to a "real" ppi value of 200, which is slightly lower than on the Galaxy S II (that uses a Super AMOLED Plus with RGB pixel structure). Some claim that a PenTile panel needs around 420 ppi to qualify as a Retina display and that is probably also the reason why Retina is nowhere to be found on the specs sheets of neither Galaxy Note nor Galaxy Nexus. If you are keen on a Samsung smartphone you might even find that the screen in the Galaxy S II is better. But the iPhone 4 and iPhone 4S still lead the pixel race. Some people say they never notice the PenTile pixel structure but it is just like a stain on a carpet; once you see it, it is hard to disregard."
In general, FlatpanelsHD complains about the blurriness and color banding that has affected PenTile displays in the past, along with a lack of power efficiency. We emailed Nouvoyance, who created the technology, to see if these gripes are still present in their technology, but we have yet to hear back. In any case, it's just something to consider when you're engaged in an lengthy argument about gadgets with a fellow spec geek. [FlatpanelsHD]