Mac Pro is the fastest, most powerful Mac ever. It features Intel Xeon processors, and can be configured with up to 12 processor cores. Powerful ATI Radeon HD graphics are perfect for advanced 3D modeling and rendering. You can add up to 64GB of memory, four PCI Express expansion cards, and up to 8TB of hard drive storage. And Mac Pro comes standard with OS X Lion, the worlds most advanced desktop operating system.