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Enter the dual-core PowerPC G5 processor: one silicon chip with two independent 2.5GHz processor cores. Now take two of those chips and you have the Power Mac G5 Quad, for groundbreaking quad-core processing.

With four processing cores, you’ll have more 64-bit resources: more L2 cache, more Velocity Engines, and more double-precision floating-point units. Videographers can edit more footage, filmmakers can produce more real-time effects, designers and photographers can process more higher-resolution images, and researchers can crunch through data sets for faster results. Compare a quad-core Power Mac G5 to the fastest dual-processor G5 ever built, and you’ll experience up to 69 percent faster performance running popular professional applications. Or make that up to three times faster, if you’re comparing with a Power Mac G4.

PowerPC G5 Chip

Do the Math

The new dual-core PowerPC G5 combines two processor cores on a single silicon chip, providing double the computational power in the same space as a single-core processor. With four processor cores, applications can take advantage of four 1MB L2 caches, four 128-bit Velocity Engines, and eight double-precision floating-point units for a radical increase in desktop performance.

Memory stack.

64-Bit Memory Addressing

The dual-core PowerPC G5 joins forces with Mac OS X v10.4 Tiger to enable 64-bit computation. With 42 bits of physical address space, the PowerPC G5 supports a colossal 4 terabytes (4TB) of system memory. Although it’s not currently feasible to purchase 4TB of RAM, the advanced architecture of the PowerPC G5 allows for plenty of growth in the future.

More practical and still far more than a typical PC, the Power Mac G5 can be configured with 16GB of addressable memory. Such large quantities of memory enable the system to contain a complex 3D model, massive digital images, a scientific simulation, or a sequence of video entirely in RAM.


64-Bit Computational Power

The other advantage provided by the 64-bit PowerPC G5 is the ability to perform multiple simultaneous 64-bit floating-point and integer calculations. The PowerPC G5 features full 64-bit data paths and data registers, allowing it to express the extreme precision needed for floating-point mathematics and to express integers up to 18 billion billion. By contrast, a 32-bit processor must break these types of computations into multiple pieces — requiring multiple passes through the processor and slowing down application performance.

Eight Double-Precision Floating-Point Units

The PowerPC G5 core contains two double-precision floating-point units, each capable of performing a multiply and an add at the same time. This means a Power Mac G5 Quad, with four processor cores and a total of eight floating-point units, can complete up to sixteen 64-bit floating-point operations in a single cycle.

Such immense computational power accelerates applications in many fields, including audio creation, 3D content creation, and scientific visualisation and analysis — resulting in performance levels far beyond those of previous Power Mac generations.(1)

Linpack chart

Four Velocity Engines

The Velocity Engine in each core is optimised with two independent queues and dedicated 128-bit registers and data paths for efficient instruction and data flow. This 128-bit vector processing unit accelerates data manipulation by applying a single instruction to multiple data at the same time, known as SIMD processing. With four Velocity Engines, the Power Mac G5 can achieve up to 76.6 gigaflops — almost double the performance of its predecessor.(1)

Gigaflop chart

Vector processing is useful for transforming large sets of data, such as manipulating an image or rendering a video effect. Each Velocity Engine pipeline speeds up these tasks by processing up to 128 bits of data — in four 32-bit integers, eight 16-bit integers, sixteen 8-bit integers, or four 32-bit single-precision floating-point values — in a single clock cycle. That works out to 16 simultaneous 32-bit floating-point operations on a Power Mac G5 Quad.

  1. Testing conducted by Apple in September 2005 using preproduction 2.5GHz Power Mac G5 Quad units; all other systems were shipping units. For complete test information, download the Technology Overview.
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