It's time to upgrade my 2006 Mac Pro. Far and away the best machine I've ever owned, but the video card won't support Final Cut Pro X, and my 13" MacBook Pro just doesn't cut it for video editing. The two machines in the refurb store that have my eye right now are the quad-core 3.2GHz machine and the 8-core 2.4GHz machine. The only task where I wish my current Mac Pro were faster is in running NIK's DeFine noise-reduction on 21 megapixel digital images. And of course, for video, there's never "too fast." So which of those two machines would do better with video and photo post-processing? Are 8 cores running at 2.4GHz going to outperform four running at 3.2, or vice versa?