Apple introduced the Mac Pro as a fully customizable quad-core computer. The buyer can choose from two dual-core Intel Xeon Woodcrest at 2.0, 2.66, or 3.0 GHz. As little as 1 GB of RAM or as much as 16 GB. 160, 250, or 500 GB in drive bay one, and optionally 500 GB in bays 2-4.