Three elements are necessary.
1. Your computer must have a CPU that supports 64-bit processing. AMD’s Opteron and Athlon 64 processors have offered this for a couple of years. In spring 2005 Intel introduced the Pentium 4 600 Series, with support for “Extended Memory 64 Technology” (EM64T). Intel Zeon CPUs also support 64-bit but are most often used in networking and business environments.
2. A 64-bit operating system (OS). Microsoft released the 64-bit version of Windows XP recently and is offering a free crossgrade for 64-bit processor owners willing to trade in their existing XP Pro license. This OS supports up to 128GB of RAM and 16 terabytes of virtual memory.
3. An application that’s written to take advantage of 64-bit processing. Steinberg Cubase SX3 can address up to 4GB of RAM when used with a 64-bit operating system. Steinberg claims this doubling of maximum available RAM resources is accompanied by a “significant performance boost” when used with 64-bit processors. Cakewalk offers a “Technology Preview” of SONAR x64, complete with a selection of DirectX plug-in effects and instruments rewritten for 64-bit processing.