I'm in the market for a new Mac Pro. I see a good deal on the previous generation quads on Amazon. $2,080 for the 2009 2.66GHz quad vs. $2,424 for the 2010 2.8GHz quad. So the 2010 quad is 16% more expensive vs. 5% higher clock speed. Is there any reason to buy the new 2.8 over the old 2.66?