By Prince McLean

Published: 10:00 AM EST (07:00 AM PST)

Performance overview: 64-bit Snow Leopard

Running Geekbench as a 64-bit app, the benchmark suite ran significantly faster, with a 3-5% improvement in floating point and memory tests and a huge 20% jump in integer performance, resulting in a 9% boost to the overall score on the same hardware. Like all other 64-bit capable consumer Macs, the latest 27" iMac boots Snow Leopard by default using the 32-bit version of the Mac OS X kernel (which is still capable of running 64-bit applications), which we used to run the 64-bit Geekbench suite.

After manually activating the 64-bit kernel on the new iMac, running the 64-bit benchmarks again did not result in any significant difference; all scores were either the same or higher or lower within a range of ten points (less than 0.5% difference). This indicates that invoking Snow Leopard's 64-bit kernel has a minimal impact on performance when using consumer applications within 4GB of installed RAM. Using 64-bit applications (when available) on the 32-bit kernel has a major impact on performance, however. This contributes to Snow Leopard's overall speed boost on 64-bit Intel Macs, as nearly all bundled applications on Snow Leopard outside of the Adobe Flash plugin and certain background tasks are all 64-bit.

For users worried about whether they are running (or can run) Snow Leopard using its 64-bit kernel, this should provide reassuring evidence that the reason Apple only activates the 64-bit kernel by default on the Xserve is because the bit mode of the kernel currently has little impact on general performance for consumers. On the other hand, running the 64-bit kernel requires that all kernel extensions (including hardware drivers and certain VPN software) and printer drivers also be 64-bit. Snow Leopard's default behavior opts for compatibility, and this does not appear to have any discernible impact on performance.

Far more important to consumers will be the introduction of additional 64-bit third party apps, including those still missing from Apple, such as iLife, iWork, and Pro Apps including Final Cut Studio, Logic Studio, Aperture, and FileMaker Pro. Compiling existing apps to run as 64-bit programs appears to provide an easy ~10% boost in performance, which primarily comes from advantages in avoiding 32-bit penalties related to the legacy Intel x86 architecture prior to AMD's x64 enhancements.

The New 27" iMac in Review

The latest iMacs deliver a significant performance boost, better specs overall and much greater RAM expansion. Along with its capability to act as a DisplayPort monitor, the new model and its incredible widescreen display delivers a great overall package at a new lower price. It's also great to see Apple offering RAM upgrades at prices that aren't simply absurdly unreasonable.

The iMac's glossy screen will not appeal to some users, but the display looks amazing, and is a significant jump up in quality compared to last year's iMacs. If you're in the market for a new iMac, the new model makes a great, well rounded upgrade. If you're considering a new large display, you might even be tempted to get the iMac just for that, and leave it running in the background as a server or distributed processing node. The only possible downside might be if the noises we heard are typical and not something that can be addressed by AppleCare or a software update.

Users wanting to add their own RAM have four slots to work with, but anyone hoping to add another hard drive must watch out for the new vendor-specific temperature sensors, an issue that we didn't see mentioned anywhere on Apple's site. Overall, the new big screen iMac promises to be a popular addition to Apple's lineup, and deliver a great performance to dollar ratio.

Unlike many similarly configured generic PC offerings, the iMac lacks a TV tuner and Blu-Ray player features. There are a variety of low cost third party TV tuners for the Mac, but few options for Blu-Ray movie playback. The best option for Blu-Ray playback is currently Sony's PlayStation 3, although it does not allow iMac users to output video to their fancy new screen. Of course, Apple doesn't want to sell users a new HD disc format, it wants people to download its own iTunes videos instead, which don't offer the same kind of high resolution experience.

Rating 4 out of 5



Pros:
Brighter, very high quality screen with monitor input function
Great overall value and reasonably priced upgrade options
Fast performance options for CPU and GPU
SD card slot is a nice convenience
Wireless keyboard and mouse now included in price

Cons:
Bluetooth keyboard occasionally lost contact with the machine
Sleep whine from fan was annoying but may be a limited issue
No PC-style TV/Blu-Ray convergence features

Where to Buy

Below is a table of iMac prices from leading Apple Resellers that was extracted from AppleInsider's MacPriceGuide. Currently, ClubMac.com is offering the lowest price on the new all-in-one desktops after a mail-in-rebates and an addition $15 discount coupon available only to AppleInsider readers. However, this coupon expires one week from today on November 12th.




To see the $15 discount and achieve the final prices above, you must first add the iMac to your shopping cart. The $15 discount is reflected as "Instant Discount(s)" during checkout, after the items have been placed in your shopping cart.

For similar offers on the remainder of Apple's Mac product line, please see our full-fledged Mac Price Guide.