Macworld has reviewed the entry-level, quad-core Mac Pro. Here’s James Galbraith:
It should come as no surprise that the entry-level Mac Pro didn’t perform as well as the high-end $3999 stock Mac Pro, which was 11 percent faster overall. Despite the double-digit performance differences, many of the results were nearly identical between the two stock Mac Pros: iTunes import, file copy, zip, unzip, and PCMark Office tests were all within one percent between the two systems. The 6-core system was much faster at tests that could take advantage of the additional processing cores; HandBrake was 23 percent faster than on the quad-core Mac Pro, Cinebench CPU test was 30 percent faster, and MathematicaMark was 36 percent faster.
If I were in the market for a Mac Pro, I’d probably go with the 6-core machine just to future-proof things a bit. That said, the $2,999 machine doesn’t seem like a throw-away option Apple included just to hit a price point.