Thunderbolt iMac: The perfect compromise
Apple's blazing-fast, elegant, and economical everything-in-one goes where ordinary desktops can't
Thunderbolt iMac: Benchmark results
If you're considering pressing a notebook into desktop service, iMac's superior performance should factor into your decision. Benchmarks comparing a 3.1GHz 27-inch Core i5 iMac to a 2.2GHz Core i7 17-inch MacBook Pro show iMac to be the clear performance champ, and the thread-intensive SPECjbb2005 benchmark doesn't even highlight the benefits of iMac's desktop-speed hard drive. Although it's possible to configure high-end portables like MacBook Pro with a 7,200-rpm hard drive and an upgraded CPU, you'll spend a lot to construct a notebook that's in iMac's league.
I don't have a current Mac Pro for testing, but benchmarks run against an older eight-core Nehalem Mac Pro reveal iMac's generational advantage. The iMac scales remarkably well to SPECjbb2005's multithreaded workloads, even when pushed to run eight threads without the benefit of Hyper-Threading. The iMac has the headroom to handle a demanding mix of foreground and background tasks without bogging down the user interface. (See the table of SPECjbb2005 results.)
Notes: Thunderbolt iMac configured with 3.1GHz quad-core Core i5 CPU, 6MB L3 cache, 4GB of 1,333MHz DDR3 RAM; Thunderbolt MacBook Pro configured with 2.2GHz quad-core Core i7 CPU, 6MB L3 cache, 4GB of 1,333MHz DDR3 RAM; Core 2 Duo MacBook Pro configured with 2.8GHz dual-core Core 2 Duo CPU, 6MB L3 cache, 4GB of 1,067MHz DDR3 RAM; Nehalem Mac Pro configured with two 2.93GHz quad-core Intel Xeon CPUs, 8MB L3 cache, 12GB of 1,066MHz DDR3 RAM.
The iMac's CPU is capable of some impressive feats on its own, but it's Apple's ingenious pairing of top-shelf tech from rivals Intel and AMD that makes iMac tick. Mac OS X's OpenGL-based GUI suits any Mac, but it's clearly designed to run on a modern discrete GPU. AMD's Radeon HD 6000M-series GPUs are a Goldilocks fit for iMac: They have enough juice to smooth OS X's scrolling and transitional animations and deliver satisfying frame rates on 3D games, while avoiding the overkill in heat, power, noise, and cost that a Radeon HD 6000-series desktop GPU would bring to the design. Apple's decision to go with mobile GPUs may elicit a lukewarm response from hard-core gamers, but that's not iMac's niche. The iMac's architecture is optimized for Mac OS X, and vice versa.
Notes: Thunderbolt iMac configured with AMD Radeon HD 6970M discrete GPU; Thunderbolt MacBook Pro configured with AMD Radeon HD 6750M discrete GPU, Intel HD 3000 integrated GPU; Core 2 Duo MacBook Pro configured with Nvidia GeForce 9600M GT discrete GPU, Nvidia GeForce 9400M integrated GPU; Nehalem Mac Pro configured with AMD Radeon HD 4870 discrete GPU. Core 2 Duo MacBook Pro results are not directly comparable to Intel and AMD GPUs because a different shape is used, but do reflect relative performance.