From the Lab: Penryn iMacs show promise

The 3.06GHz iMac released earlier this week—Apple’s first consumer machine to top the 3GHz mark—turned in an impressive performance in Macworld Labs testing, approaching the speed of the standard Mac Pro configuration.

In the rest of our initial tests of the updated iMacs, we found that new 2.4GHz iMac outpaced the 2GHz model it replaces as Apple’s entry-level iMac. However, the revamped machine’s next-generation Core 2 Duo chip was not enough to push it past the 2.4GHz iMac introduced last August, though there are other hardware factors at play.

The iMacs we’ve tested are part of the updated iMac line announced Monday by Apple. Externally identical to the aluminum-clad iMacs released in August 2007, these new Macs include a number of under-the-hood improvements, highlighted by the addition of newer Core 2 Duo processors, code-named Penryn. The more energy-efficient Penryn chips also boost the amount of shared L2 cache to 6MB from 4MB in the older iMacs. The new systems also include faster RAM, a speedier frontside bus and—in the case of the 24-inch iMac—an option to include a more powerful graphics card.

Apple offers three standard iMac configurations: two 20-inch models that either run on 2.4GHz or 2.66GHz processors (up from 2GHz and 2.4GHz, respectively); and a 24-inch iMac with a 2.8GHz processor (up from 2.4GHz). Standard hard drive capacities and graphics cards remain unchanged, with the entry-level iMac featuring a 250GB hard drive and ATI HD 2400 GT graphics with 128MB of video RAM. The other two iMacs both feature a 320GB hard drive and ATI HD 2600 Pro graphics with 256MB of video RAM. Despite the changes to the iMac line, pricing remains the same—$1,119 for the entry-level iMac, $1,499 for the mid-range model, and $1,799 for the 24-inch system.

Just as the previous lineup included a faster, optional processor upgrade (in that case, the 2.8GHz Core 2 Extreme) available in a build-to-order configuration, this year’s lineup offers a 3.06GHz Core 2 Duo processor, available as a $200 add-on to the standard 24-inch configuration or in a $2,199 build-to-order system that also features an Nvidia GeForce 8800 GS graphics card with 512MB of memory. (When we bought our iMacs at the Apple Store in Palo Alto, Calif., the salesperson referred to this $2,199 system as the “Ultimate” configuration, though additional RAM and hard drive options exist.)

We have all three standard iMacs plus the build-to-order system in the Lab, undergoing testing. And though we are not completely finished testing all of these systems, we wanted to share the results of the two systems we think will be of greatest interest to our readers: the $1,199 2.4GHz iMac and the $2,199, build-to-order 3.06GHz iMac.

Penryn iMac Benchmarks

Speedmark 5 Adobe Photoshop CS3 Cinema 4D XL 10.5 Compressor iMovie HD iTunes 7.5 Quake 4 Unreal Tournament 2004 Finder
OVERALL SCORE SUITE RENDER MPEG ENCODE AGED EFFECT MP3 ENCODE FRAME RATE FRAME RATE ZIP ARCHIVE
24-inch iMac Core 2 Duo/3.06GHz * 279 0:47 0:43 1:21 0:36 0:49 86.9 111.2 3:36
20-inch iMac Core 2 Duo/2.4GHz (April 2008) 230 0:59 0:54 1:45 0:47 1:02 30.9 78.7 4:26
20-inch iMac Core 2 Duo/2.4GHz (August 2007) 239 0:54 0:54 1:56 0:49 0:58 61.9 90.2 4:14
20-inch iMac Core 2 Duo/2GHz (August 2007) 204 1:03 1:06 2:17 0:58 1:10 31.4 66 5:17
24-inch iMac Core 2 Extreme/2.8 GHz * 268 0:48 0:47 1:45 0:41 0:50 61.9 97.8 3:45
Mac Pro Xeon/Dual 2.8GHz Quad Core 301 0:49 0:15 0:51 0:32 0:48 74.3 109.8 3:51
>Better <Better <Better <Better <Better <Better >Better >Better <Better

Best results in red. Reference systems in italics. * denotes build-to-order configuration.

Speedmark 5 scores are relative to those of a 1.5GHz Core Solo Mac mini, which is assigned a score of 100. Adobe Photoshop, Cinema 4D XL, iMovie, iTunes, and Finder scores are in minutes:seconds. All systems were running Mac OS X 10.5.2 with 2GB of RAM, unless otherwise indicated. The Photoshop Suite test is a set of 14 scripted tasks using a 50MB file. Photoshop’s memory was set to 70 percent and History was set to Minimum. We recorded how long it took to render a scene in Cinema 4D XL. We used Compressor to encode a 6minute:26second DV file using the DVD: Fastest Encode 120 minutes - 4:3 setting. In iMovie, we applied the Aged Film effect from the Video FX. menu to a one minute movie. We converted 45 minutes of AAC audio files to MP3 using iTunes’ High Quality setting. We ran the net timed demo in Quake 4 at 1024x769 with high quality settings and multiprocessing enabled. We used Unreal Tournament 2004’s Antalus Botmatch average-frames-per-second score; we tested at a resolution of 1,024 by 768 pixels at the Maximum setting with both audio and graphics enabled. We created a Zip archive in the Finder from a 2GB folder. For the Professional Application Multitasking suite, we recorded how long it took Photoshop to run our standard test suite while a longer Cinema4D task and our Compressor encode test ran in the background.—MACWORLD LAB TESTING BY JAMES GALBRAITH, JERRY JUNG, AND BRIAN CHEN

In our overall performance testing suite, Speedmark 5, the new entry level iMac posted a respectable score of 230, about 13 percent faster than last August’s 2GHz iMac. The newer system also outperformed its entry-level predecessor in every test except for Quake 4, which was a virtual tie.

However, compared to last year’s 20-inch 2.4GHz iMac, the new machine was 3 percent slower overall, even with the newer Penryn chip. However, a couple of component differences may explain this result—the older 2.4GHz iMac had a larger hard drive and a better graphics card than the new entry-level model; it also costs $300 more than the new system. In that context, then, the Speedmark result isn’t that disappointing.

One noteworthy win for the newer 2.4GHz iMac over the older model was in our Compressor MPEG encoding test. We believe that reflects the new machine’s 1,066MHz frontside bus with memory running at 800MHz. The older 2.4GHz iMac had a frontside bus of 800MHz and memory running at 667MHz.

Our build-to-order “ultimate” iMac posted a Speedmark score of 279, just 7 percent slower than the $2,799 8-core 2.8GHz Mac Pro. The Mac Pro excelled in the few the applications that can take advantage of more than a couple of processing cores, like Compressor and Cinema 4D, but in other tests (like Photoshop), the custom iMac’s faster, processor trumped the more plentiful, multi-core (and slower) processors in the high-end Mac Pro.

As we mentioned, the customized iMac replaces the standard ATI HD 2600 Pro graphics with 256MB of video RAM with an Nvidia GeForce 8880 CS graphics card with 512MB DDR video memory. (The card is also available as a $150 option for the 24-inch iMac.) If you’re a gamer, this could be money well spent, as the custom iMac was not only faster than last year’s build-to-order iMac at both our Quake 4 and Unreal Tournament game tests, but it also bested the standard configuration Mac Pro as well.

Check back soon for Macworld’s full review of the new iMacs including test results for the 2.66GHz and 2.8GHz models.

[James Galbraith is Macworld Lab director.]

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