G5





The G5 is a microprocessor used in the newest Apple Macintosh computers. The
G5 was publicly announced in June 2003 by Apple Computer. G5 is Apple's term
for the IBM manufactured microprocessor called PowerPC 970, and stands for
the fifth generation of Power PC microprocessors. It's a true 64-bit design
(with full backward compatibility for 32-bit code without rebooting).

Models of Apple's Power Macintosh announced in June 2003 incorporated these
microprocessors running at speeds of 1.6, 1.8 and, in a dual-chip version,
2.0 GHz. The G5 can communicate through its frontside bus at up to half its
internal clock speed; a 2 GHz G5 thus has a 1 GHz frontside bus, and due to
the 64-bit processor the G5 has a RAM ceiling of eight gigabytes (a full
four gigabytes above current THEORETICAL limits on 32-bit processors) . The
technology behind the IBM PowerPC 970 (based on IBM's POWER4 design paired
with a 128-bit, 162-instruction SIMD unit for Apple's use) and that of the
Power Macintosh G5 is cutting edge for a desktop system as of its
introduction.

In June 2003, Steve Jobs, Apple Computer CEO, announced that chips running
at speeds of 3.0 GHz would be available "within a year". The move that Apple
is making to 64-bit hardware suggests the G5 will have a long future ahead of it.

Apparently work has been started at IBM on the POWER5 processor series but
no official word has been made on what the project's goals are.