PowerPC G3

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G3 is the designation for the G eneration 3 of the PowerPC processor family. Like the previous second generation processors ( PowerPC 603 and 604 ), it was jointly developed by Apple , IBM and Motorola .

G3 is also the slang term for the Power Macintosh G3 computers from Apple.

A radiation-protected variant of this processor ( RAD750 ) serves as the main processor of the Mars Reconnaissance Orbiter probe, and has long been one of the most powerful operating processors outside of the earth or its orbit. The Gaia space probe has 21 of the 750FX processors. The seven video processing units of the probe work simultaneously with three processors each. A logic continuously compares the results of the three processors, recognizes a faulty processor and automatically restarts it in a millisecond with the values ​​of the other two processors, without the overall computing process being interrupted. It is the most powerful computer that has been operated in space until then.


The G2 processors had the disadvantage that they were based too much on the early, partly still experimental PowerPC 601 processor , which was developed for a different environment with a different background and with a lack of experience. The G3 processors, however, have been optimized for use as CPUs for workstation computers; i.e. for the Power Macintosh model series. In addition, operation with two processors at the same time was now also possible, which, however, caused problems with the L2 cache and corresponding performance losses for the two individual processors.

Processors of the series

PowerPC 750 from IBM
  • IBM / Motorola PowerPC 740 - without external L2 cache
  • IBM / Motorola PowerPC 750 - basic model
  • IBM PowerPC 750CX - mainly designed for mobile use
  • IBM PowerPC 750CXe - increased speed
  • IBM PowerPC 750CL
  • IBM PowerPC 750FX - further increased speed (clock frequencies above 1 GHz possible)
  • IBM PowerPC 750GX
  • IBM PowerPC 750VX - G3 with Altivec support
  • RAD750 - radiation-resistant version for space applications

Video game consoles with PowerPC 750: