Apple overhauls iMac line with larger models

Apple announced a major update to its iMac line of desktop computers, replacing the old 20- and 24-inch models with new 21.5-inch and 27-inch models featuring a true widescreen 16×9 aspect ratio and impressive high-end features previously found only in the Mac Pro line, including the first quad-core processor ever in an iMac.

As is common with new Apple products, these new iMacs offer more features than their predecessors, but start at the same $1199 base price. The new models feature a new enclosure that's wider, to encompass the wider aspect ratio, with an all-aluminum back.

The displays on both models are backlit by LEDs, marking the first time Apple has integrated this bright, instant-on lighting in a desktop computer. The 21.5-inch display has a resolution of 1920×1080 pixels, the equivalent of a 1080p HDTV, and features 90 percent of the resolution of the old 24-inch iMac model. The massive 27-inch model's resolution is 2560×1440 pixels. Both use the IPS display technology used previously only on high-end iMacs, meaning both systems have good color fidelity and a 178-degree viewing angle without color shift.

Following the lead of the MacBook Pro line, these new iMac models feature an SD card slot right below the optical-drive slot on the computer's right side. The systems ship standard with the new version Apple's wireless keyboard and the new Apple Magic Mouse, also announced Tuesday. (Users who prefer wired input devices will be able to opt for them as a configure-to-order option from Apple, for no price change.)

These new models offer a new RAM ceiling of 16GB, double the maximum memory of previous models. The iMacs can now can be configured with up to 2TB of storage.

The low-end 21.5-inch iMac model, priced at $1199, features a 3.06GHz Intel Core 2 Duo processor, 4GB of RAM, a 500GB hard drive, and Nvidia GeForce 9400M video circuitry. A $1499 model features the same specs other than a 1TB hard drive and the Radeon HD 4670 video card. The $1699 27-inch model features the same specs as the $1499 model, but with the 27-inch display. All of those models are available immediately.

The $1999 high-end model, which won't be available until November, brings the iMac product line to new performance heights. It's powered by a 2.66GHz Intel Core i5 quad-core processor and features a Radeon HD 4850 video card. A configure-to-order option will swap in the Intel Core i7 chip for the Core i5.

Based on the Linfield processor that's part of the same Nehalem chip family found in the Mac Pro line, the Core i5 is a four-core processor that features “turbo mode,” technology that allows the chip to shift automatically from a slower clock-speed, four-core mode into a faster-speed mode with only two cores active. The turbo-mode speed of the Core i5 chip can go as high as 3.2GHz, and the turbo-mode speed of the Core i7 can good up to 3.46Ghz.

In a clever touch, all these new iMacs have a new feature that dramatically increases their versatility. Via a series of adapters Apple says will be available shortly, users will be able to attach external display sources, such a DVD players or even other computers, to the iMac's display. At that point, those sources will take over the iMac's display, effectively turning it into an external monitor or an HDTV.

Before this update, the last round of iMacs were released in March of 2009 and featured a 20-inch model powered by a 2.66GHz Core 2 Duo processor for $1199, and a series of 24-inch models with processors at 2.66, 2.93, and 3.06GHz for $1499, $1799, and $2199 respectively.