Apple makes a big hullabaloo when it comes time to refresh its iPhones and MacBooks, but today the iMac received a nice, and relatively quiet, update to Intel's Haswell line of processors. And new Nvidia 700 series GPUs. And faster flash storage. And 802.11ac Wi-Fi. And they're available now in Apple's store.
The low-end 21.5-inch iMac runs on a 2.7GHz quad-core Haswell Core i5 processor and Intel's integrated Iris graphics, which is higher performance than the HD 5000 GPU we've seen in laptops. The step up 21.5-inch iMac, and both 27-inch models, use Nvidia's GPUs for graphics and faster i5s clocked at 3.4GHz.
The iMacs, of course, be upgraded to i7 processors. Each model also runs on a different Nvidia GPU: the 750M for the step-up 21.5-inch, the 755M for the base 27-inch, and the 775M for the step-up 27-inch. Only the most expensive model, the $2000 27-inch iMac, offers the option to upgrade to an Nvidia 780M GPU with 4GB of video memory.
Also, the PCIe flash storage improvements will only benefit iMac buyers who upgrade to Apple's fusion drives, which combine solid state and hard drive storage. By default, every model comes with a 1TB hard drive. A 1TB fusion drive costs an extra $200, and Apple is claiming a 50 percent performance improvement thanks to its new flash storage. 802.11ac support will also speed things along if you happen to have an AC router around to help.