Below we provide a performance review of the PowerBook G4/550 compared to the iBook G3/600 when running OS 10.1. In most of our OS 10.1 tests, the G4 PowerBook bested the higher clocked iBook ... sometimes by a large margin. This was not always the case with the testing we did comparing these machines when running OS 9.2.1.The G4 processor of the PowerBook is the chip that Apple markets as having a 'Velocity Engine'. The more technical name for this enhanced processing capability, is 'AltiVec Technology' which is carried out by a 128-bit vector engine.

"The AltiVec unit is an enhanced integer or floating processing unit. It provides a new 128-bit processing unit, 32 vector registers and over 160 new instructions that allow for the processing of data in a pipeline"

Aside from the G4's ability to improve performance significantly in certain programs tuned to take advantage of it, (see the AltiVec Fractal test below, to see just what can be done), OS X itself, must have been tuned by Apple to, in some of its parts, take advantage of the Velocity Engine. This would account for some of the relative speed improvement of the PowerBook when running OS 10.1 over the PowerBook when running similar tests under 9.2.1.

Of course raw performance capability is not the only criteria to weigh when selecting a portable computer. But if your rely on your machine to do heavy lifting the results below should give you some guidance on what kind of work each excels at. Be sure to check out the links under "Additional Resources" for more information on these machines.

"Real World" Tests

The tests below are from our suite of real world application tests. These tests feature a diverse selection of applications commonly used by the Mac community. The test suite was designed to render an accurate and well rounded picture of a machine's performance. All of the tests below were timed with a stopwatch. The times are then converted to percentages relative to the iBook G3/600, which is set to 100%. For all scores, higher numbers are better.

Finder Tests

Drive performance is what probably makes the most difference in the above test

This was an interesting result because the perforrmance was almost the opposite when running under 9.2.1

This result was similar under both OS's.

Perhaps the better graphics sub-system is what is helping the PowerBook here. But is could be that AppleScript is tuned to take advantage of the G4. This test creates and destroys 1,000 windows. See the program site for more info

Large document is scrolled from one end to the other using Classic OS through OS 10.1

Large Document & Database Type Test

This test takes place in a large AppleWorks document. Both these machines have a 256K L2 Cache. Though the PowerBook is faster, both are hobbled by the small cache size

Number Crunching & Rendering Tests

See iMovie

In the processor intensive tasks above you can see the power of the G4 coming into full force. The Fractal program has been highly tuned to take advantage of the G4 and is precisely the type of work that the G4 was made for.

Encoding/Decoding Tests

This test gets movie files ready for Web streaming

Converting QuickTime movies to DV allows you to import them into iMovie

Where possible, most Apple programs have been tuned for the G4 processor .. see iTunes

Well you can't win at everything .. see StuffIt