64-bit power.

Leopard is the first universal operating system to seamlessly support both 64-bit and 32-bit applications. There’s no need to upgrade drivers, and you can even stick with your existing printers, storage devices, and PCI Express cards. Leopard lets you take advantage of 64-bit processing power without having to use command-line applications, servers, and computation engines. Learn more

UNIX compliant.

What makes Leopard so great? The fully compliant UNIX technology. It can compile and run all your existing UNIX code. It helps you make the most of multicore systems. It puts a new tabbed-interface terminal at your fingertips. And it gives Leopard the solid groundwork for hundreds of great new features on every Mac Pro. Learn more

Multicore. Multithreaded.

Leopard is designed to take full advantage of eight cores of processing power. The new Leopard scheduler allocates tasks more efficiently across these multiple cores and processors. A new multithreaded network stack speeds up networking. And Mail, Address Book, and Font Utility have all been updated to be fully multicore ready. Learn more