by The update of Apple’s iMac range has come less than a year after November 2012’s radical redesign, so it’s no surprise that it’s an internal refresh — Apple’s upgraded the processors to Intel’s newest chips, the Wi-Fi to the new, fast 802.11ac standard, and the graphics cards to Nvidia’s new GeForce 7-series GPUs. Solid-state storage — available as an option when ordering from the Apple Store online — is now PCIe-based, for faster SSD and Fusion Drives.
Last year, a beautiful new slimline build replaced the iMac’s old chassis. The optical drive was dropped due to lack of space, but we got USB 3.0 ports, two Thunderbolt ports, a great new screen with a huge reduction in reflections, and new speakers that really lifted the iMac’s internal audio. We got the same sizes of screen, too — both 21.5-inch screens and 27-inch displays. This refresh retains all of that, but has quite a few changes inside.
The most important upgrade is the switch to Haswell processors, the fourth generation of Intel’s Core “i” series. Quad-core Core i5 chips are standard across the board, with Core i7 CPUs available as a custom option in the more expensive model in each screen size (but not the cheaper versions rated here). The off-the-shelf processors support Intel’s Turbo Boost feature, where underused resources can be reallocated to give a temporary increase in speed, but not HyperThreading, which enables each core to appear as two virtual cores. The optional Core i7 has both of these features, so it’s a big step up for intensive tasks.
The two 21.5-inch iMacs include 2.7GHz and 2.9GHz processors respectively, which are the same clock speeds as the previous generation, but with a performance boost overall. The 27-inch models offer 3.2GHz and 3.4GHz processors. Storage is 1TB across the board, but once again, the 21.5-inch models use 5,400rpm drives and the 27-inch iMacs use faster, 7,200rpm drives. Custom upgrades are available, including replacing the hard drive with an SSD or a Fusion Drive, which combines a hard drive with 128GB of flash storage for fast access to the operating system and regularly used data. The iMac is very difficult to upgrade after purchase, so if these options interest you, be sure to buy a custom build online.
Off-the-shelf memory is again 8GB of 1600MHz DDR3 RAM. Also in common with the 2012 iMacs, the 27-inch models’ RAM can be user-upgraded after purchase by opening a hatch behind the stand. The 21.5-inch version has no such hatch, so if you need more memory, again make sure you upgrade it when purchasing from Apple.
The new iMac range takes a step up in graphics too, with double the video memory in most models. The more expensive 21.5-inch model gets an Nvidia GeForce GT 750M with 1GB video memory, up from a GeForce GT 650M with 512GB. The cheaper 27-inch model’s GeForce GT 755M with 1GB is up from a GeForce GTX 660M with 512GB, and the top-of-the-range large-screen iMac has a GeForce GTX 775M with 2GB instead of a GeForce GTX 675MX with 1TB. The only exception is the cheaper 21.5-inch iMac, which drops the GeForce GT 640M used in the 2012 release and doesn’t replace it at all, instead opting for Intel’s new Iris Pro graphics — a significant step up from the technology in the integrated graphics Intel normally uses. While it still shares memory with the CPU, it also has a 128MB cache of very fast on-chip eDRAM. Intel boldly claims it can match a discrete GPU for performance. And all of this is available at the same price point as last year’s models.
In our tests, the 2.7GHz 21.5-inch iMac’s Iris Pro graphics put in a mixed performance. It ran Doom 3 at an impressive 172.8 frames per second compared to the 2.9GHz model’s 222fps, and its 3D rendering capabilities tested using Cinebench’s OpenGL benchmarks were also pretty close. When we tested the graphics using the Unigine Heaven 4.0 benchmarking tool, however, it only managed 9.7 frames per second, compared to the 19.1fps in the more powerful machine. It was a similar story using NovaBench; the Iris Pro iMac scored a mere 79, whereas the model featuring the GeForce GT 750M discrete GPU achieved 246. In the real world this will make very little difference to your web surfing, emailing, and word processing, but if you want to play games at higher resolutions, including the native 1080p of the 21.5-inch iMac’s screen, or do any other 3D work, we’d say you’re definitely better off paying extra for the costlier version.
