Lab tested: 27-inch Core i5 iMac/3.6GHz (BTO)

After posting our benchmark results for the four new standard configuration iMacs, several readers had the same request: test the new 3.6GHz Core i5 iMac, a built-to-order (BTO) option for the 3.2GHz Core i3 iMacs. You spoke, we listened and we ordered a custom 27-inch iMac with the 3.6GHz Core i5 dual core processor, though we upped the ante by adding a second drive to the system, a 256GB solid-state drive (SSD) to complement the 1TB 7200-rpm drive that comes standard. We tested the system twice (once booted from the hard drive and then booted from the SSD) and the results are intriguing.

The drive and processor upgrades add $750 and $200 respectively to the cost of the standard $1699 27-inch 3.2GHz Core i3 iMac, bringing the price to $2649.

Processor boost

To see how this faster, dual-core processor affected performance, we ran Speedmark 6 with everything installed on the hard drive and unmounted the SSD. Compared to the results of the standard 27-inch 3.2GHz Core i3 iMac, we found the custom iMac to be 8 percent faster in our overall system performance test suite, Speedmark 6.

The 3.6GHz model was faster in most tests, with impressive gains in Cinebench (14 percent), MathematicaMark (16 percent) and Compressor (14 percent). The only two tests that the 3.6GHz custom system failed to outperform the standard 3.2GHz system was iPhoto import, which was just one second faster on the standard iMac, and our HandBrake rip and encode tests, which took the 3.6GHz system nearly twice as long to complete.

As we found in recent DVD ripping tests of the standard iMacs, Apple doesn’t use just one supplier for components like the SuperDrive. In fact, we’ve seen three different SuperDrive mechanisms in our five new iMacs. Although they all boast very similar specifications, one of these mechanisms, the HL DT ST DVDRW GA32N, performs very slowly in our HandBrake test. Our theory is that the HL uses riplock, a technology that aims to improve DVD watching on computers by slowing down the rotational speed of the disc for quieter operation. The stock iMac came with a Pioneer DVRTS09, which performs well. There’s no way to know what mechanism your iMac will come with, so if you rip DVDs frequently, you’ll just have to hope for something other than the HL.

Comparing the custom dual core 3.6GHz Core i5 iMac (running from the 7200-rpm hard drive) to the quad core 2.8GHz Core i5 iMac, we see that the four cores win out in terms of overall performance by 8.5 percent. But looking at individual test results, we see that the biggest difference in performance was, again, HandBrake, which took nearly three times as long for the 3.6GHz Core i5 iMac to complete. The quad core 2.8GHz Core i5 iMac also excelled in the few tests that take full advantage of multiple processors, like MathematicaMark, Cinebench and Compressor. Other tests, like Photoshop, iTunes, Finder file unzipping, and Aperture showed that faster-but-fewer processors can sometimes perform better than more-but-slower processors. If you’re not a heavy user of the few high-end programs that put to use all of those multiple cores, it might be wiser to spend $200 on the Core i5 processor upgrade to the stock 27-inch $1699 iMac than to spend an extra $300 on the quad core 2.8GHz Core i5 iMac.

SSD results

Speaking of spending money, we also tested the 3.6GHz Core i5 BTO iMac booted from a 256GB SSD. When we received the iMac, everything was installed on the SSD—the operating system, applications, and documents. The secondary hard drive was empty. So that’s how we tested it.

It’s $600 to swap the standard 1TB 7200-rpm hard drive for a 256GB SSD; $750 to install both a 1TB hard drive and a 256GB SSD. One would hope to see an appreciable difference in performance. I must say that the SSD did not disappoint.

When using the SSD as the boot disk, we saw a 12 percent overall performance increase over the same iMac booted from the hard drive. As you’d expect, processor intensive application results were unaffected by the choice of hard drive. Unzipping a file in the Finder, however was 41 percent faster on the SSD; duplicating a file was 38 percent faster. iPhoto was 17 percent faster and iTunes encode test was 12.5 percent faster when using the SSD.

And though startup time is no longer part of our Speedmark score, we found that the iMac started up 22 percent faster when booting from the SSD than from the hard drive. Likewise, launching applications proved to be much quicker with the SSD. The SSD iMac launched GarageBand and opened a project in 5 seconds, while it took the same iMac running off the hard drive 12 seconds to launch and open the same project. Launching multiple applications showed even more improvement, with the SSD iMac launching four applications in just 3 seconds, a task that took 19 seconds on the hard drive iMac.

We’ve run into issues in the past with some SSDs slowing down over time. We plan on doing a lot more testing of the internal SSD and will report our findings in a future article.

Comparing the results to the quad core 2.8GHz Core i5 iMac using a 7200-rpm hard drive, we found the SSD-based dual core 3.6GHz Core i5 iMac to be 5 percent faster in our Speedmark test suite. The handful of applications that take advantage of extra cores remained faster on the  quad core 2.8GHz Core i5 iMac, but many of the tests benefited from the combination of faster drive and faster-but-fewer processors. Photoshop, Aperture, iMovie, iTunes, Finder tasks and iPhoto were all faster on the SSD-equipped dual core 3.6GHz Core i5 iMac.

While we still have not received the new Mac Pros, we did look at the older quad core 2.66GHz Xeon Mac Pro and found the SSD-based dual core 3.6GHz Core i5 iMac to be 12 percent faster overall. The Mac Pro was faster at MathematicaMark, CineBench, iMovie import and of course HandBrake, but the majority of the tasks were completed faster by the custom iMac.

We are expecting one more custom iMac configuration and new Mac Pros to arrive in the very near future. Check for benchmarks of these new systems.

27-inch Core i5 iMac/3.6GHz (BTO) benchmarks

Mark 7
Call of
Duty 4
Finder Parallels
WorldBench 6
27-inch iMac 3.6GHz
Core i5 dual core
228 0:37 1:23 7.19 6:00 1:34 1:22 0:55 0:49 82.1 0:24 4:05 2:51 0:19
27-inch 3.6GHz
Core i5 dual core
(7200-rpm hard drive)
203 0:38 1:23 7.2 5:59 1:38 1:32 0:59 0:56 82 0:41 4:08 3:02 0:23
27-inch 2.8GHz
Core i5 quad core
217 0:40 1:09 10.1 5:36 1:47 1:17 0:57 0:58 88.1 0:44 4:03 1:01 0:22
27-inch iMac 3.2GHz
Core i3
188 0:42 1:37 6.2 6:58 1:59 1:42 1:05 0:59 81.4 0:44 4:45 1:37 0:27
Mac Pro 2.66GHz
quad core
203 0:38 1:00 11.13 6:17 1:36 1:09 1:18 1:10 49.3 0:44 4:27 1:15 0:27

Best results in bold. Reference systems in italics.

How we tested. Speedmark 6 scores are relative to those of a 2.13GHz Core 2 Duo MacBook, which is assigned a score of 100 (higher scores are better). Call of Duty score is in frames per second (higher is better). MathematicaMark is a performance score (higher is better). All others are in minutes:seconds (lower is better). All iMacs were tested with OS X 10.6.4 and 4GB of RAM. The 2.66GHz Mac Pro was tested with OS X 10.6.1 and 3GB of RAM. We duplicated a 1GB file, created a Zip archive in the Finder from the two 1GB files and then unzipped it. We converted 90 minutes of AAC audio files to MP3 using iTunes’ High Quality setting. In iMovie ’09, we imported a camera archive and exported it to iTunes using the Mobile Devices setting. We ran a Timedemo at 1024-by-768 with 4X anti-aliasing on in Call of Duty 4. We imported 150 JPEGs into iPhoto ’09. 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 used Compressor to encode a .mov file to the application\'s H.264 for video podcast setting. We ripped a DVD chapter to the hard drive. We recorded how long it took to render a scene with multiprocessors in Cinebench. We ran the Evaluate Notebook test in MathematicaMark 7. We ran the WorldBench 6 multitasking test on a Parallels 5 VM running Windows 7 Professional. We timed the import and thumbnail/preview creation time for 150 photos in Aperture.—Macworld Lab testing by James Galbraith, McKinley Noble, Blair Hanley Frank, and Chris Holt.

SSD benchmarks

Startup File duplicate GarageBand Multiple apps
27-inch 3.6GHz Core i5 dual core
0:22 0:13 0:05 0:03
27-inch 3.6GHz Core i5 dual core
(7200-rpm hard drive)
0:27 0:21 0:12 0:19

Best results in bold.

How we tested. Times are in minutes:seconds (lower is better). All systems were tested with 4GB of RAM. We timed startup times without network connection. We duplicated a 1GB file, we timed how long it took to launch a Garageband project by clicking on the project's icon. We recorded the time it took to launch Photoshop, Microsoft Word, iTunes and Safari.—Macworld Lab testing by James Galbraith and McKinley Noble

[James Galbraith is Macworld’s lab director.]

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