What versions of the PowerPC are
available?
PowerPC 601 & 601+
The 601 was the first PowerPC CPU to be developed as a result of
the cooperation of Motorola, IBM, and Apple. The PowerPC was a
fresh design, but owes a great deal to IBM's previously developed
'Power' RISC series. In particular, the
601 incorporated and modified the user-level POWER instructions. It
has an eight-word instruction fetch bus from the cache, four-entry
translation shadow buffer, and 32 bit general purpose registers.
The memory management uses 52-bit virtual and 32-bit real
addressing, four block address translation registers. It also has a
32 KB cache, 32-bit address bus, and 64-bit data bus, support for
graphics coprocessor (such as a graphics card) and multiprocessor
support. The fastest release of the chip was clocked at 100MHz.
The 601+ is basically the same as the 601, except for the
implementation of a 05u CMOS 2.5V process, which effectively makes
it go slightly faster and draw less power.
The PowerMac 601 machines were short-lived offering few
advantages over the 68040 CPU used in most Macs of the time.
Macintosh 68k emulation slowed the processor further, providing
system performance equivalent to a 68030 Mac.
Machines that use it:
Apple PowerMac
PowerPC 602
Motorola adverts at the time, promoted the 602 as the perfect
processor for 'low-cost home entertainment devices with
audio/video, multimedia, or anything that has complex graphic
requirements'. It is was developed for portable PPC markets, such
as laptops and has gained some use in the embedded market. It is
slightly slower than the 601, but does not require as much power.
Machines that use it:
3D0 M2 (unreleased)
PowerPC 603 and 603e
For the first time PowerMacs could execute 68k software faster than
the 68040. The launch of the 603 PowerMacs resulted in the
appearance of numerous game titles and high-end applications.
The 603 and 603e are low power units designed for desktop
computers and notebooks. The 603 features a separate 8K instruction
and data cache and executes up to five instructions in five
parallel units- the fixed point, floating point, branch, system,
load/store units. The PPC 603 uses 8k physically addressed
instruction and data cache, whilst the 603e offers a 16k version.
It also features dynamic power management, a processor clock
multiplier of 1x, 1.5x, 2x. 2.5x, 3x, 3.5x, and 4x from the bus
clock.
The PowerPC 603e is a higher performance 603 with a faster clock
and larger cache. It was originally known as the 603+.
Machines that use it:
Amiga PowerUP accelerators, PowerMac Apple Pippin (China+Hong Kong
only), BeBOX (discontinued), A/Box (canceled), The Sega
SaturnUpgrade (unreleased).
PowerPC 604
The 604 and 604e are designed for complex processing tasks and is
considerably faster than the 603. The processor is software and bus
compatible with the 601, 603 and 603e processors. The 604e doubles
the physically addressed instruction and data cache by using a 32k
version for a greater speed increase.
Machines that use it:
Phase5 PowerUP accelerators, PowerMac, A/Box(canceled)
PowerPC G3
The G3 is a considerable improvement on the 604 design rendering a
great deal of software incompatible. The developers of BeOS
suffered due to a lack of information on porting their OS to the
new processor. The AmigaG3 cards offer a number of improvements
over previous versions, moving 68k processing into software, which
in turn, reduces the cost of manufacture.
Machines that use it:
iMAC, PowerMac, AmigaOne
PowerPC G4 "MAX"
No sooner had G3 been announced that G4 suddenly became the new
standard. Released during 1999, the G4 processor is the most
advanced version of the PowerPC so far. It consists of 10.5 million
transistors, occupying 83 square millimeters, fabricated in a 0.2um
process with copper interconnects. The G4 also includes the new
"MaxBus" designed for bus clocks of 100MHz or over, and improved
symmetric multiprocessing performance.
The G4 doubles the L2 cache of the PowerPC 750 (aka G3) including a
2Mb version and doubles the backside bus width to 128 bits. Other
design improvements include the Altivec technology, a multimedia
extension similar to Intel's MMX.
Machines that use it:
PowerMac, AMIRAGE K2.
External Links
PowerPC
Architecture: A High-Performance Architecture with a
History
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