[Matt Devino]"It should work OK as long as you put as much RAM in it as you can afford and get the faster quad-core. A mac pro with 8-cores is optimal. "
That is not the best advice,
YES, you can work with RED footage on any intel based mac you have to take into account that RED cameras captures images at the extreme high end of the spectrum.
iMacs are consumer products and not IMHO designed for that kind of work, I think you would be frustrated at what can be accomplished on a computer with no video out and only FW for connectivity. RED does not recommend anything less than a desktop, stating that laptop editing needs to be at 1K frame or less. ( Med Proxy size)
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