Here is a relevent benchmark. The top of the line iMac has a Sandy Bridge 2600, and the 980X is the desktop version of the equivilant server part. 980X vs 2600

Here is a relevent benchmark. The top of the line iMac has a Sandy Bridge 2600, and the 980X is the desktop version of the equivilant server part. 980X vs 2600 video transcoding: 24s vs 29.1s (lower is better) But there are still 2 CPUs in the Mac Pro, so you can double performance; it should be 2.5x faster still. Ivy Bridge, which features in the new MacBook Pros, and likely iMacs soon, nets another 10% or so for the same clock speed over Sandy Bridge. Haswell will likely be the point at which a quad core Haswell chip roughly equals a 6 core Westmere chip (not bad for a 3 generation gap). http://www.anandtech.com/show/4083/the-sandy-bridge-review-intel-core-i7-2600k-i5-2500k-core-i3-2100-tested/16 http://www.anandtech.com/show/4083/the-sandy-bridge-review-i... Edit: Another commenter pointed out that AE has CUDA acceleration. In that case, even a mid range graphics card would be faster than two high end CPUs.