21.5- and 27-inch iMacs (Late 2009)

Featuring bigger and better screens and shiny new mice, the physical changes to the aluminum iMac in this update are the most dramatic since it was introduced over two years ago, but the speed improvements are marginal at best.

The new iMacs are currently available in three standard configurations. The entry-level $1199 iMac and the $1499 iMac both feature 21.5-inch displays and 3.06GHz Core 2 Duo processors; these models replace the 20-inch iMac ( ) released earlier this year. The current high-end iMac is a 27-inch model with a 3.06GHz processor. Apple also announced a new 27-inch iMac with a 2.66GHz Intel Core i5 processor that sells for $1999, but Apple says it won’t be available until later this month. The 27-inch models replace the “Early 2009”  24-inch iMacs ( ).

Ratio redo

The changes with the iMac start with the screen. Replacing the previous 20- and 24-inch screen with a 16:10 aspect ratio are 21.5- and 27-inch displays at 16:9, more suitable for widescreen HDTV video. The 21.5-inch display has a native resolution of 1920-by-1080, while the 27-inch display has a resolution of 2560-by-1440. The aluminum faceplate at the bottom of the screen is narrower than before, and the aluminum border around the screen is gone. At first glance, you might mistake the new iMacs for HDTVs—in fact, the new 27-inch iMac has support for a VESA Mount Adapter Kit ($29) for mounting on a wall.

Switch on the iMacs, and you’ll notice that the LED backlit screens on both the 21.5- and 27-inch models are a bit brighter than their predecessors. Look even closer at the 21.5-inch iMac, and you’ll notice that its colors are much better than the 20-inch iMac. That’s because Apple thankfully now uses 8-bit displays across the iMac line—the 6-bit dithered display used in the 20-inch iMac is gone (we hope).

Both of the new displays use in-plane switching (IPS) technology, which is supposed to help maintain image quality when viewing the screen at extreme angles. Looking at the new iMacs at different angles, I had a difficult time noticing any color shifting. When compared side-by-side against the previous iMacs, the 20-inch iMac screen looks like a mess, while the new iMac screens maintained their color integrity.

There’s one major issue with the screen that, for many, is a deal-breaker: the glass on the display and its glossy effect. The glossy effect makes colors pop and blacks deep and rich, but you can see your reflection in the glass. When using the iMac as a desktop computer, I’ve learned how to see past the glare and reflections, but many others cannot develop such tolerance—and I’m not saying you should. Glare is a problem if you’re in a group gathered around the 27-inch iMac that’s being used as an HDTV. In fact, because of the glare, you might reconsider using the 27-inch iMac as a HDTV. However, it’s now been two years since the first aluminum iMac with glass was introduced, and there are no signs that Apple is interested in offering a matte screen option.

Go inside

All three of the new iMacs use 3.06GHz Core 2 Duo processors with 3MB of shared Level 2 cache. The three new iMacs have the option to upgrade to a 3.33GHz Core 2 Duo processor with 6MB of shared Level 2 cache for an extra $200. The previous iMacs used Core 2 Duo processors at 2.66GHz, 2.93GHz, and 3.06GHz, but with 6MB of shared Level 2 cache.

The new iMacs come standard with 4GB of RAM, installed as a pair of 2GB 1066MHz DDR3 SO-DIMMs. The new iMacs have four memory slots; Apple actually leaves two slots open so you can add more RAM without having to replace the stock memory—a nice touch. The iMac can support up to 16GB of RAM, but a 16GB upgrade option is available only with the 27-inch 3.06GHz model for $1400. The other iMacs have an upgrade option of 8GB (an extra $200) installed as four 2GB SO-DIMMs. You can easily install RAM yourself through the RAM slots located at the bottom of the screen.

For graphics, the $1199 21.5-inch iMac uses a Nvidia GeForce 9400M, which uses 256MB of memory that’s shared with the main memory. Both the $1499 21.5-inch iMac and the $1699 27-inch iMac use an ATI Radeon HD 4670 with 256MB of dedicated video memory. The 27-inch iMac is the only model in the line that has a graphics upgrade option, an ATI Radeon HD 4850 with 512MB of memory ($150).

All of the new iMacs have 7200 RPM hard drives. The $1199 iMac has a 500GB drive, and interestingly, Apple does not offer upgrade options for more storage. The other two iMacs have 1TB drives, and you can opt for a 2TB drive instead for an additional $250. All of the iMacs have SuperDrives, and next to the SuperDrive slot is a new SD card slot that can read SD and SDHC memory cards that are used in digital cameras.

Ports, video in, and more

Like previous iMacs, the ports are located on the back of the iMac, on the lower left side. There is a headphone/optical digital audio output minijack, an audio line in/optical digital audio input minijack, four USB 2.0 ports, one FireWire 800 port, a Mini DisplayPort, and a Gigabit Ethernet port. If you have FireWire 400 peripherals, you’ll have to supply your own FireWire 400-to-FireWire 800 adapter.

The 27-inch iMac’s Mini DisplayPort has an very interesting new feature. It has video-in capability, so you can connect a external video source like a MacBook, Blu-ray player, or even a Playstation 3, and use the 27-inch iMac as a monitor. According to Apple, the computer is still on when in this mode, and you can press Command-F2 on your keyboard to switch between the computer and the external video source. Apple also said that you can connect a video source while the iMac is on, so there’s no need to shut down. To use the 27-inch iMac’s video in, you need to have either a DisplayPort-compliant source like a MacBook, or you can use an adapter for a non-DisplayPort device, such as an HDMI-to-Mini DisplayPort video-in adapter. However, Apple said it has no plans to produce such adapters, leaving it up to third-party manufacturers.

To strengthen the possibility of using the iMac as part of an entertainment center, Apple upgraded the speaker system. The new speakers are a vast improvement over previous models, producing richer sound with better bass response and louder volume. You’ll still want to use external speakers to fill a room larger than 20-by-20 feet, but for bedrooms, offices, dens, and smaller living rooms, the built-in speakers have enough power.

The iMacs come standard with an iSight camera, Wi-Fi, and Bluetooth. Apple includes a new version of the Wireless Keyboard, which now uses two AA batteries instead of the three AA batteries required in its predecessor. Apple also includes the new Magic Mouse ( ). Apple does not include its new Apple Remote, and if you want one, you’ll have to shell out an extra $19.

Performance

Macworld Lab ran our complete suite of benchmark tests to gauge the speed of the new iMacs. What’s intriguing about the new iMacs is that they all use the same 3.06GHz Core 2 Duo processor with 3MB of shared Level 2 cache and 4GB of RAM. If you think that the new iMacs would post similar benchmark scores, you are correct—in almost all of our tests, the three new iMacs posted similar times. When comparing the total amount of time it took to complete all 17 of our timed tests, the three new iMacs were within 30 seconds of each other.

The key difference between the three iMacs is the graphics card. The $1199 21.5-inch iMac with its Nvidia GeForce 9400M integrated graphics chip posted a rate of nearly 22 frames per second in our Call of Duty benchmark. That’s acceptable for gameplay, but dramatically slower than frame rates of over 65 fps by the $1499 21.5-inch iMac and the $1699 27-inch iMac, both of which use an ATI Radeon HD 4670 graphics card.

When compared to its predecessors, the speed gains with the new iMacs are marginal at best. The $1199 3.06GHz 21.5-inch iMac had nice improvements over the 2.66GHz 20-inch iMac Core 2 Duo (which was $1,199 at its release earlier this year) in our Aperture, Cinebench, Compressor, Pages, and Zip Archive tests. But in some of our tests—Adobe Photoshop CS4, MathematicaMark 7, and Call of Duty 4—the speed increase was small, if there was an increase at all.

Generally speaking, the 27-inch 3.06GHz iMac had an overall performance that was about the same as the the previous high-end iMac, the 24-inch 3.06GHz iMac (see the Complete 17 Tests column in the chart below). The new 27-inch 3.06GHz iMac showed slight improvements over the 24-inch 2.93GHz iMac of the previous generation; the biggest performance difference between these two iMacs is in the Call of Duty test, in which the 27-inch 3.06GHz iMac clocked more than 20 fps over the 24-inch 2.93GHz iMac.

Macworld’s buying advice

Overall, there isn’t much of a performance difference between the Early 2009 iMacs and these new machines. The Late 2009 iMacs are really about the new displays—and the displays are impressive. The screens in the 21.5-inch iMacs are a welcomed change over the 20-inch, 6-bit displays, and the IPS technology in the new iMacs preserves the image quality at any viewing angle.

The $1199 21.5-inch iMac is a very attractive deal, but you’ll get more storage space and better graphics performance if you step up to the $1499 21.5-inch iMac. The $1699 27-inch iMac can do double duty as part of a home entertainment center for watching videos. If you want want the very best performance and you can’t wait, consider the $1499 21.5-inch iMac or the $1699 27-inch iMac.

However, if you can wait, and performance is your top priority, hold off until we get the new $1999 quad-core, 27-inch Intel i5-based iMac. We’ll have a full review of it when we get our hands on one.

[Roman Loyola is a Macworld senior editor.]