Lab Report: New 27-inch Core i5 iMac/3.1GHz speed results

At a Glance
  • Apple 27-inch Core i5 iMac/3.1GHz (quad-core)

    Macworld Rating

On Tuesday, Apple released an updated line of iMacs, featuring quad-core Sandy Bridge Intel processors and Thunderbolt ports. Macworld Lab has all four standard configuration models, and the results for the $1999 27-inch iMac are in. The results do not disappoint, with the new iMac besting the previous generation of standard-configuration iMacs. The new 3.1GHz iMac even bested the performance of some impressively-equipped build-to-order models we've tested previously.

The $1999 iMac was the first to arrive in our lab and the first to be tested. At the heart of this iMac is a 3.1GHz Core i5 quad-core processor. This iMac also has a 1TB 7200-rpm hard drive, and AMD Radeon HD 6970M graphics with 1GB of video memory.

Our overall system performance test suite, Speedmark 6.5, shows the new system to be 16 percent faster than the previous high-end standard configuration iMac, a 27-inch 2.8GHz Core i5 quad-core model with a 1TB 7,200-rpm hard drive, and ATI Radeon HD 5750 graphics with 1GB of dedicated RAM. (Apple considered the older 27-inch 2.8GHz Core i5 iMac a BTO option, but the online Apple Store didn’t treat it like one, so we decided to treat it like a standard configuration model.)

In our iTunes encode test, the new iMac was 22 percent faster than the 27-inch 2.8GHz Core i5 iMac. The new iMac was also 18 percent faster in our Handbrake test, 20 percent faster in the Cinebench graphics test, 21 percent faster in the Cinebench CPU test, and 16 percent faster in our MathematicaMark tests.

27-inch Core i5 iMac/3.1GHz benchmarks

Speedmark 6.5 Score
27-inch iMac Core i5 3.1GHz 227
21.5-inch iMac Core i3 3.06GHz (Mid 2010) 174
21.5-inch iMac Core i3 3.2GHz (Mid 2010) 179
27-inch iMac Core i3 3.2GHz (Mid 2010) 177
27-inch iMac Core i5 2.8GHz (Mid 2010) 196
27-inch iMac 2.93GHz Core i7 (BTO, Mid 2010) 225
27-inch iMac 3.6GHz Core i5 (BTO, Mid 2010) 199
21.5-inch iMac 3.06GHz Core 2 Duo (Late 2009) 129
27-inch iMac 2.66GHz Core i5 (Late 2009) 195
15-inch MacBook Pro 2.2GHz Core i7 (Early 2011) 206
Mac Pro 3.33GHz Xeon Westmere six-core (BTO, Mid 2010) 263

Higher scores are better. Reference models in italics. Best result in bold.

Like the older 27-inch 2.8GHz Core i5 iMac, all of the new standard-configuration iMacs support Turbo Boost, which can give more processing power to individual cores when needed. And also like the older 27-inch 2.8GHz Core i5 iMac, all of the new standard-configuration iMacs don't have Hyper Threading, a technology that presents the OS with two virtual cores for each physical core.

Comparing the new system to last year’s BTO models, we see less of a difference in performance. Just two Speedmark points separate the new 3.1GHz Core i5 iMac from the 2.93GHz Core i7 quad-core BTO iMac. The 2.93GHz model, like all 2010 iMacs, does not use Sandy Bridge processors, but it does support both Hyper Threading and Turbo Boost. In applications such as Cinebench and MathematicaMark, which can take advantage of eight virtual cores, the 2.93GHz BTO iMac outperformed the new 3.1GHz iMac.

Another 2010 BTO model, the 27-inch 3.6GHz Core i5 iMac, used a dual core processor at a faster clock speed. In terms of overall performance, the new standard 3.1GHz Core i5 iMac outperformed the 3.6GHz 2010 BTO iMac by 14 percent. In applications that make efficient use of four processors (Cinebench, Mathematica, and Handbrake), the new iMac was dominant, finishing 35 percent, 67 percent and 42 percent faster, respectively. In many tasks, however, having faster but fewer processors is an advantage, as can be seen in zipping and unzipping folders, and opening a Word document in Pages.

Compared to the 15-inch 2.2GHz Core i7 quad core MacBook Pro, the new 3.1GHz Core i5 iMac was 10 percent faster overall, and a few seconds faster in almost all of our individual application tests.

Compared to a recent six-core 3.33GHz Xeon Westmere Mac Pro with 8GB of RAM, the Mac Pro was about 15 percent faster overall than the new iMac. The iMac was a little faster in the graphics tests and iTunes encode tests, but considerably slower in most tasks, especially MathematicaMark and Cinebench CPU tests.

Speedmark 6.5 individual application test results: 27-inch Core i5 iMac/3.1GHz benchmarks

Duplicate
1GB
File
Zip
2GB
folder
Unzip
2GB
folder
Pages '09
Open
Word Doc
27-inch iMac Core i5 3.1GHz 20 144 48 70
21.5-inch iMac Core i3 3.06GHz (Mid 2010) 19 166 42 77
21.5-inch iMac Core i3 3.2GHz (Mid 2010) 19 160 42 67
27-inch iMac Core i3 3.2GHz (Mid 2010) 20 161 43 76
27-inch iMac Core i5 2.8GHz (Mid 2010) 21 170 44 76
27-inch iMac 2.93GHz Core i7 (BTO, Mid 2010) 17 157 36 71
27-inch iMac 3.6GHz Core i5 (BTO, Mid 2010) 17 140 36 65
21.5-inch iMac 3.06GHz Core 2 Duo (Late 2009) 20 177 40 85
27-inch iMac 2.66GHz Core i5 (Late 2009) 22 179 43 76
15-inch MacBook Pro 2.2GHz Core i7 (Early 2011) 23 159 50 76
Mac Pro 3.33GHz Xeon Westmere six-core
(BTO, Mid 2010)
18 148 26 62

Results are in seconds. Lower results are better. Reference models in italics. Best result in bold.

Speedmark 6.5 individual application test results: 27-inch Core i5 iMac/3.1GHz benchmarks

iTunes 10
AAC to
MP3
encode
Import
movie
archive to
iMovie '09
iMovie '09
export to
iTunes 10
for iPhone
Call of
Duty 4
framerate
27-inch iMac Core i5 3.1GHz 74 66 51 88.5
21.5-inch iMac Core i3 3.06GHz (Mid 2010) 95 103 69 78.3
21.5-inch iMac Core i3 3.2GHz (Mid 2010) 91 101 68 78.4
27-inch iMac Core i3 3.2GHz (Mid 2010) 91 100 68 78.2
27-inch iMac Core i5 2.8GHz (Mid 2010) 95 78 56 88.1
27-inch iMac 2.93GHz Core i7 (BTO, Mid 2010) 92 61 55 88.3
27-inch iMac 3.6GHz Core i5 (BTO, Mid 2010) 80 90 61 79.0
21.5-inch iMac 3.06GHz Core 2 Duo (Late 2009) 123 97 102 19.1
27-inch iMac 2.66GHz Core i5 (Late 2009) 101 82 60 87.5
15-inch MacBook Pro 2.2GHz Core i7 (Early 2011) 83 70 55 81
Mac Pro 3.33GHz Xeon Westmere six-core
(BTO, Mid 2010)
81 48 48 88.3

Call of Duty 4 results are based on framerate; higher results are better. All other test results in the above chart are in seconds; lower results are better. References models in italics. Best result in bold.

Speedmark 6.5 individual application test results: 27-inch Core i5 iMac/3.1GHz benchmarks

iPhoto '09
200 JPEG
import
Photoshop
CS5 action
HandBrake
0.9.4
encode
Cinebench
R11.5
graphics
27-inch iMac Core i5 3.1GHz 28 53 209 38
21.5-inch iMac Core i3 3.06GHz (Mid 2010) 35 60 405 25.4
21.5-inch iMac Core i3 3.2GHz (Mid 2010) 34 58 391 27.4
27-inch iMac Core i3 3.2GHz (Mid 2010) 35 59 392 27.3
27-inch iMac Core i5 2.8GHz (Mid 2010) 36 55 256 31.9
27-inch iMac 2.93GHz Core i7 (BTO, Mid 2010) 29 53 208 34.8
27-inch iMac 3.6GHz Core i5 (BTO, Mid 2010) 33 55 340 31.0
21.5-inch iMac 3.06GHz Core 2 Duo (Late 2009) 42 62 569 6.4
27-inch iMac 2.66GHz Core i5 (Late 2009) 38 57 267 30.7
15-inch MacBook Pro 2.2GHz Core i7 (Early 2011) 52 55 220 35
Mac Pro 3.33GHz Xeon Westmere six-core
(BTO, Mid 2010)
27 55 144 34

CineBench R11.5 Graphics results are a score; higher results are better. All other test results in the above chart are in seconds; lower results are better. Reference models in italics. Best result in bold.

Speedmark 6.5 individual application test results: 27-inch Core i5 iMac/3.1GHz benchmarks

Cine-
bench
R11.5
CPU
Mathe-
matica
Mark 7
Parallels
World-
Bench
Multitask
test
Aperture
3 import
and
process
Multi-
tasking
27-inch iMac Core i5 3.1GHz 85 11.7 247 107 58
21.5-inch iMac Core i3 3.06GHz (Mid 2010) 157 6.1 340 125 78
21.5-inch iMac Core i3 3.2GHz (Mid 2010) 152 6.3 333 121 75
27-inch iMac Core i3 3.2GHz (Mid 2010) 152 6.23 332 123 75
27-inch iMac Core i5 2.8GHz (Mid 2010) 108 10.1 290 118 65
27-inch iMac 2.93GHz Core i7 (BTO, Mid 2010) 77 12.5 282 108 62
27-inch iMac 3.6GHz Core i5 (BTO, Mid 2010) 130 7.0 293 109 72
21.5-inch iMac 3.06GHz Core 2 Duo (Late 2009) 229 4.3 355 137 88
27-inch iMac 2.66GHz Core i5 (Late 2009) 112 9.7 300 118 65
15-inch MacBook Pro 2.2GHz Core i7 (Early 2011) 81 11.4 278 118 61
Mac Pro 3.33GHz Xeon Westmere six-core
(BTO, Mid 2010)
48 19.2 253 101 59

MathematicaMark 7 results are scores; higher results are better. All other test results in the above chart are in seconds; lower results are better. Reference models in italics. Best result in bold.

How we tested. Speedmark 6.5 scores are relative to those of a 2.4GHz Core 2 Duo Mac mini (Mid 2010) with 2GB of RAM, which is assigned a score of 100. We duplicated a 1GB file, created a Zip archive in the Finder from the two 1GB files and then unzipped it. We converted 135 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 200 JPEGs into iPhoto '09. The Photoshop Suite test is a set of 23 scripted tasks using a 50MB file. Photoshop’s memory was set to 70 percent and History was set to Minimum. For our multitasking test, we timed the Photoshop test again, but with the iTunes MP3 encoding and file compression tests running in the background. We used Handbrake to encode four chapters from a DVD previously ripped to the hard drive to H.264. We recorded how long it took to render a scene with multiprocessors in Cinebench and ran that application's OpenGL, frames per second test. We ran the Evaluate Notebook test in MathematicaMark 7. We ran the WorldBench 6 multitasking test on a Parallels 6 VM running Windows 7 Professional. We timed the import and processing time for 200 photos in Aperture.—Macworld Lab testing by James Galbraith, William Wang, and Mauricio Grijalva

We’re busy testing the other new models, so check back for more benchmarks soon. (The wait for Thunderbolt performance results will be longer, however, as the first few drives announced won't be available until this summer.) We're also working on the full review of the new iMacs.

[James Galbraith is Macworld’s lab director.]

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At a Glance
  • Macworld Rating

    Pros

    • Zippy performance from Sandy Bridge quad-core processors
    • Facetime HD camera
    • Two Thunderbolt ports
    • Fastest graphics performance in iMac line
    • Has the most configuration options

    Cons

    • Not much faster overall than the less expensive members of the iMac family
    • No anti-glare screen option
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