Taiwan newspaper DigiTimes is reporting today
that Apple will be including a Retina Display on the next iPad that will be twice the resolution of the current display. And yes, before anyone else says it: the fact that it's in DigiTimes is almost enough alone
to conclude that this report is bunk. There are, however, other valid reasons to discount the rumor.
Doubling the current iPad's resolution means going from 1024 x 768 pixels all the way up to 2048 x 1536, and as John Gruber notes
over at Daring Fireball, that's almost as many pixels as the 27" iMac at 2560 x 1440 resolution. The iMac comes with 512 MB of RAM on its graphics card, though, and the iPad has only 256 MB total, which must be shared by the CPU and the GPU. It takes a lot of memory to power that many pixels, even if such a screen could be produced cost-effectively. Which brings us to...
#2 Moore's Law.
This famous observation about semiconductor development states that the number of transistors that can be put on a given chip doubles approximately every 18 months. This trend also holds for LCD screens, which are manufactured using similar technologies. Doubling the resolution of a screen, though, doesn't mean doubling the number of pixels, but doing something more like quadrupling
it. Blogger Avery Pennarun did an interesting analysis
that figured the doubling time to get an iPhone 4-like Retina Display on an iPad-sized screen. The result: not until Christmas 2013. (However, according to this analysis, we'll have desktop-sized Retina Displays by Christmas 2015.)
Anyway, Gruber - whose Apple sources are so good he is constantly accused of being on the payroll
- says that people on the inside are telling him the iPad 2 will have a 1024 x 768 screen. He also says that there are 2048 x 1536 iPad prototypes at Apple... but that they're not for the iPad 2.
Source: Daring Fireball