The screens remain the same size -- and contrary to rumors earlier this year, were not upgraded to Retina status -- but have been reengineered, said Schiller, with the cover glass laminated to the LCD. The systems are also substantially thinner, taking a tape at just 5mm (0.2-in.) at their edge.
Resolutions remain 1920-x-1080-pixels for the 21.5-in. iMac, 2560-x-1440-pixels on the 27-in.
Schiller made much of what Apple's called "Fusion Drive," an option that combines 128GB of flash storage with a standard platter-based hard drive of between 1TB and 3TB. OS X and its bundled applications are stored on the flash drive for better performance, but other often-used applications are automatically shifted by OS X Mountain Lion to the faster flash drive.
Fusion Drive is likely not a true hybrid drive, which packs flash and platter drives in a single enclosure, but is better labeled a "hybrid solution," since the controller and software manage where data goes.
OS X Lion and Mountain Lion -- the latter is pre-installed -- have a feature dubbed "Core Storage" that lets the operating system, and thus the user, see multiple physical drives as one logical drive.
Apple's 2011 acquisition of Israeli SSD maker Anobit probably played a major role in the development of Fusion Drive.
The hybrid does not come with any standard configurations Apple has spelled out on its website, but is an option. The company has not disclosed what it will charge for the feature. Storage expert Robin Harris, who blogs on ZDNet and his own StorageMojo, has pegged the additional charge at $250 on a 1TB drive.
Analysts were generally positive about the new iMacs.
"I thought the intro of the hybrid drive was really good, and something users have been waiting for," said Ezra Gottheil of Technology Business Research.
But both Gottheil and Patrick Moorhead, principal analyst at Moor Insights & Strategy, were taken aback by the $100 price increase. Apple usually keeps prices steady during hardware refreshes, instead swapping out newer components and adding storage space and RAM, to attract customers.
"That was surprising, especially considering how well the Windows PC makers are doing with all-in-ones," said Moorhead, referring to iMac look-alikes that cost considerably less.
The 21.5-in. iMac starts at $1,299, while the 27-in. desktop begins at $1,799.
Neither will be available soon, however. The smaller iMac, Schiller said Tuesday, will ship next month -- no firmer date than that -- and the 27-in. won't appear until December.
As of Tuesday night, Apple listed the new iMacs on its online store, but was not taking pre-orders. Apple has not said why the new desktops face such long delays, nor has it responded to questions about the inability to pre-order an iMac.
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