First it's important for me to tell you about my current set up. My 2009 iMac is long in the tooth. It's a core i5 27 inch iMac. All of my media is backed up to an original 4 bay Drobo over FireWire. The computer is fast enough when browsing the web but trying to access my photos on my Drobo is just painfully slow. For instance, importing 70 raw photos to Lightroom is so slow that I can start the process and go eat dinner.
I spent a bunch of time talking to Apple engineers about the best set up for photographers and here's what I walked away with: Get the 27 inch iMac and spring for the for the 1GB graphics card instead of the base 512MB. With future versions of Photoshop you're going to want that additional graphics power.
Avoid the Fusion Drive. Apple describes it this way:
It combines 128GB of flash with a standard 1TB or 3TB hard drive to create a single storage volume that intelligently manages files to optimize read and write performance. Fusion Drive adapts to the way you use your iMac and automatically moves the files and apps you use most often to flash storage to enable faster performance and quicker access.
That's great but it doesn't make sense for professional photographers. The fastest possible set up is to stick with a pure SSD configuration and run a Drobo via Thunderbolt or USB 3.0 to house your photos (I'll explain more about the Drobo in a second). Apple confirmed that this is the fastest way to go. The base level is 128GB and is expandable up to 768GB. Really you just want enough space to run the OS and the apps you'll need. I will probably bump it up to 356GB of flash, that'll give it enough breathing room to run some of the big apps.
The new Drobo's are out and they are fantastic. I'm getting the Drobo 5D. It's blazing fast now with Thunderbolt and USB 3.0. They house up to 5 regular spinning hard drives or SSD's. I have a bunch of 3 TB drives that I'm going to put inside. With Thunderbolt connection I don't see the need to have SSD's in the Drobo just yet. You might feel differently if you're working with a lot of video. Once the cost drops a bit I might spring for them. For now I'm sticking with the old spinning drives. Drobo works by keeping your data spread across multiple drives so if one drive fails you don't have to worry about it. Simply swap out the drive with a new one and you're good to go.
Another bonus is the screen. While it's not Retina, the new iMac screen is 75% less reflective because the pixels lay just under the glass like the iPhone and Retina iPad.
The 21 inch iMacs came out in November and the 27 inch model shipped in December. I think with the new 27 inch iMacs Apple is saying forget about the Mac Pro.
