(A byte equals eight bits.) A 64-bit processor can theoretically handle 16 quintillion (or 16 billion billion) bytes of RAM.

Thirty-two bit processors are limited to a theoretical maximum of handling 4 billion bytes (4 gigabytes) of random access memory, or RAM, per task. So, microprocessors using 64-bit architecture provide higher performance than 32-bit processors by handling twice as many bits of information in the same clock cycle. A 64-bit processor is capable of handling binaries consisting of a string of 64 0s and 1s. A 32-bit microprocessor, for example, can move, add, subtract or multiply units composed of 32 0s and 1s. Microprocessors are generally defined by the amount of information they can manipulate in a given clock cycle. 'I think we're dropping a snowball down the hill,' said Rich Heye, vice president and general manager of Advanced Micro's microprocessor business unit, adding, '64-bit computing will take off faster than people think.' Soon afterward, the new chips will affect everyday computer users, for whom a new generation of media machines should offer remarkable improvements in audio and visual effects. The arrival of 64-bit desktop processors signifies a new era of computing - initially for professionals who are bumping up against the processing limits of existing PCs. Intel's Itanium chips, introduced in 2001, are 64-bit processors - although unlike the Apple and Advance Micro products, the Itanium is not a processor to which users of lesser chips can easily switch. In the Windows world, Advanced Micro Devices plans to roll out a 64-bit processor, the Athlon 64 FX, next month.

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