I'm looking to buy a second hand Mac Pro. I'm looking for the fastest machine for the cheapest price. I found a 2 x Intel Xeon X5650 @ 2.67GHz for a reasonable price. According to cpubenchmark.net this processor has a score of 7,687. So does the 2x mean that the computer has a score of 15,374? So will rendering and encoding video be twice as fast compared to one processor?