updated 08:31 pm EDT, Wed June 18, 2014
Benchmarks show multi-core apps limited by dual-core processor
The new, lower-cost iMac introduced today is definitely aimed at "light-duty" desktop users rather than those looking for greater-than-notebook power from their desktop, a new teardown and benchmark analysis has shown. While hardly surprising, the newest iMac essentially uses MacBook Air internals in an iMac form factor, and consequently has similar benchmark scores (but with something of a twist). The teardown has revealed that the 8GB RAM on the new iMac model is un-upgradable, however.
While the lower-cost iMac uses the same low-voltage chip as found in the MacBook Air (accounting for its 1.4GHz standard speed, which can increase up to 2.7GHz when required), benchmark scores differ slightly between the models. Single-core CPU benchmarks for the new iMac are directly comparable (though the iMac seems to be about 12 percent faster) to the current MacBook Air, and just slightly lower than the next model up, the 2.7GHz quad-core i5 iMac (previously the entry-level model). Multi-core benchmarks, however, are markedly lower for the new iMac than the 2.7GHz model -- 40 percent lower.
In Geekbench testing, the new iMac scored 5435 on multi-core (slightly higher than an i5-powered MacBook Air), compared to 9667 for the i5-based quad-core iMac. Of course, the cheaper iMac is limited to a dual-core i5 processor. so multi-core benchmarks were never likely to match - but Apple hasn't shipped an iMac with multi-core scores this low since 2011. The multi-core Geekbench score is roughly equivalent to the dual-core Mac mini from that same year.
Writer Andrew Cunningham of Ars Technica believes Apple may have sacrificed some multi-core speed -- which might be lightly-employed among the entry-level or light-duty users who are likely to buy the new budget iMac -- in exchange for better graphic prowess. The new iMac uses Intel HD 5000 integrated graphics, the same graphics used in the latest MacBook Air and the first-ever Mac desktop to do so. The HD 5000 features benchmark scores are comparable to some discreet graphics cards, such as the Nvidia GeForce GT 720M or an ATI Radeon HD 5570.
I'd say Apple used an Ultrabook CPU in the new iMac to avoid shipping Intel's HD 4600 GPU in anything. No desktop CPUs include HD 5000.— Andrew Cunningham (@AndrewWrites) June 18, 2014
With Yosemite, video playback and graphics-oriented Apple apps (such as iMovie, Keynote and iPhoto) increasingly relying on better GPUs, the move may actually help extend the useful life of the low-end iMac, as those buyers are much less likely to run CPU-intensive applications but do expect to maintain decent performance in the OS for several years to come. As with the lower-speed but variable CPU, Apple has made a tactical compromise aimed at real-world, typical-user performance to keep the cost down.
Another limitation made on the new budget iMac is the hard-soldering of RAM to the motherboard, making RAM upgrades impossible. The unit comes with 8GB, and there is no factory upgrade option. The new teardown by Other World Computing has revealed that the 8GB of RAM included in the unit is soldered to the motherboard, making aftermarket upgrades impossible as well. Currently, OS X Mavericks (10.9) and Yosemite (10.10) require a minimum of 2GB of RAM, but also offload much of the visual interface work to the graphics card, making RAM and CPU somewhat less important until users get into more serious graphic, GPU and CPU-intensive applications such as Adobe Photoshop.