This article describes the Velocity Engine, also known as AltiVec, which is incorporated into the new PowerPC G4 processors in the Power Mac G4 computer.

The Velocity Engine can process data in 128-bit chunks, instead of the smaller 32-bit or 64-bit chunks used in traditional processors (it's the 128-bit vector processing technology used in scientific supercomputers--except that we've added 162 new instructions to speed up computations). In addition, it can perform four (in some cases eight) 32-bit floating-point calculations in a single cycle--2-4 times faster than traditional processors.

The PowerPC G4 with Velocity Engine works with the PowerPC architecture to accelerate the data-intensive processing required by next-generation video, voice, and graphics applications. Among the G4 key features is a vector permute function capable of rearranging data in the registers--a priceless benefit when converting data from one format to another (often necessary with voice, video and graphics apps, which typically need to save data in a number of different formats). These vector processing acceleration advantages give the G4 microprocessor a significant edge when it comes to fast visualization of large data sets, and intensive math for real-time simulations. Making the G4 perfect for everything from graphics and 3D games to astronomy, the biosciences, and predictive modeling.

For an in-depth discussion of the technology, refer to the Motorola Web page on AltiVec at http://www.mot.com/SPS/PowerPC/AltiVec/index.html