Apple iMac (27-Inch/Core i7): Hail to the All-in-One Performance King

Apple's new high-end 27-inch iMacs--released late 2009--are the first all-in-one PCs to use Intel's latest Core i5 and Core i7 processors. We can tell you it was worth the wait.

Core i7 features a technology Intel calls Turbo Boost. If an application isn’t using every available core, the cores that are idle shut off, and the active cores speed up. According to Apple, this allows the processor to run up to 20 percent faster under heavy workloads; that translates to 3.46GHz in this iMac.

Armed with a 4GB of DDR3-1066 RAM, a 1-terabyte hard disk, and a 512MB ATI Radeon HD 4850 graphics chip, the Core i7 iMac scored a category-leading 128 in our WorldBench 6 general performance benchmark. That's 15 percent faster than the previous high-end 24-inch, 3.06GHz iMac that had cost $2200 earlier this year, and about 5 percent faster than the new $2000 iMac (27-inch/Core i5). Macworld's Speedmark tests showed a 16 percent difference between the Core i5 and Core i7 under OS X.

The next fastest all-in-one PC we've tested is the 21.5-inch/3.06GHz iMac from late 2009; it scored 115 in WorldBench 6. Following on are the $2000 Sony Vaio L117FX/B and $1400 Gateway One ZX6810-01: both scored 105 in WorldBench 6 (22 percent behind the Core i7 iMac). And here's the thing about rival Windows 7 all-in-one PCs. If you can take the performance hit and don't mind slightly smaller screens, you tend to get a lot more bang for your buck: multitouch displays, Blu-ray drives, more USB slots, a greater variety of integrated ports (HDMI, eSATA, xD, Memory Stick), and even HDTV tuners with Windows Media Center DVR functionality. See Best Big Screen All-in-One PCs (Over 20 Inches) for more.

As for Apple's iMac line, the whole family has been upgraded: the old 20-inch/2.66GHz and 24-inch/3.06GHz iMacs have been replaced with new 21.5-inch/3.06GHz models, plus 27-inch variations such as the iMac reviewed here. Each has an LED backlit screen covered with glass at a 16:9 aspect ratio, an integrated iSight camera, four USB 2.0 ports, one FireWire 800 port, a Mini DisplayPort, and a new SD memory card slot. In terms of connectivity, all new iMacs offer gigabit ethernet, 802.11n wireless networking, and Bluetooth 2.1+Enhanced Data Rate. The new models also have a larger RAM ceiling of 16GB (double the previous maximum), and you can add a $250, 2-terabyte storage option.

High-definition video looks beautiful on the iMac's 27-inch (2560-by-1440 resolution) display. And games purr along, too. Our gaming tests of the Core i7 and Core i5 iMacs (which, other than the processor, have identical specifications) returned largely identical results that blow away other all-in-one PCs. For instance: 134, 112, and 72 frames per second in our Unreal Tournament 3 tests (run at 1024 by 768, 1680 by 1050, and 1920 by 1200; high-quality settings turned on). The next best gaming performance comes from the Gateway One ZX6810-01. It managed 71 fps to the iMac's 112 fps in the same test.

With both the 2.66GHz Core i5 iMac and the 2.8GHz Core i7 iMac, Apple has not only blurred the line between consumer and professional systems, it has darn near erased it. Unless you absolutely require additional PCI cards, multiple internal hard drives, or a lot of RAM, the Core i7 iMac makes a strong case for the being the go-to system for most performance-hungry Mac professionals.

--Danny Allen and James Galbraith