Apple M9592LL Technology Overview - Page 11

Technology Overview 11 Power Mac G5 Up to 25 percent faster memory throughput With support for DDR2 memory, data throughput on the new Power Mac G5 is 25 percent faster than previous Power Mac G5 models and up to three times faster than the Power Mac G4. 128-bit DDR2 at 533MHz 128-bit DDR at 400MHz 64-bit DDR at 333MHz 2.7 GBps 8.5 GBps 6.4 GBps Almost twice the graphics throughput The 16-lane PCI Express graphics interface increases throughput to up to 4 GBps, almost double that of AGP 8X in previous Power Mac G5 models. 16-lane PCI Express AGP 8X 2.1 GBps 4 GBps Up to twice the PCI throughput PCI Express delivers a radical increase in throughput compared with the expansion technologies on previous Power Mac G5 systems (PCI-X and PCI) and Power Mac G4 systems (PCI). Eight-lane PCI Express Four-lane PCI Express PCI-X 64-bit, 133MHz PCI 64-bit, 33MHz 0.25 GBps 1 GBps 1 GBps 2 GBps 533MHz DDR2 Main Memory The new 128-bit memory controller in the Power Mac G5 supports DDR2 main memory running at speeds up to 533MHz. In addition to writing data at a double rate, or twice the rate of the clock speed, the memory controller increases e∑ciency by reordering read and write operations. By addressing two banks of SDRAM at the same time, the new Power Mac G5 can reach a memory throughput of up to 8.5 GBps. That represents a 25 percent increase over the latest Power Mac G5 and triple the throughput of the fastest Power Mac G4. With its 64-bit processor architecture, the Power Mac G5 can address more memory than any previous Macintosh and many desktop PCs. All Power Mac G5 systems can hold up to eight 2GB DIMMs for up to 16GB of memory. For users in mission-critical and compute-intensive environments, there's also the option of ECC (Error Correction Code) main memory, which allows automatic correction of single-bit errors and detection of multiple-bit errors. This high-speed, high-capacity memory architecture enables graphics, video, audio, and scientific applications to run radically faster. Enormous files and data sets can be loaded into RAM for rapid access by the PowerPC G5-without having to access system storage. Data can be retrieved from memory 40 times faster than from the hard drive. In fact, accessing the first critical word of data from memory is 60,000 times faster than from a hard drive, so manipulation and analysis of data can be performed at remarkable speeds. PCI Express Graphics With the introduction of PCI Express architecture comes a new 16-lane PCI Express graphics interface that supports the latest graphics controllers and delivers up to 4 GBps of data throughput. By supplying up to 150 watts of power to the primary graphics processing unit, the new Power Mac G5 provides the headroom for highperformance, next-generation graphics processors and applications, enabling even higher resolutions for stunning realism. For more information about graphics cards, Apple displays, and graphics technologies, see the "Workstation Graphics" section. PCI Express Expansion The all-new PCI Express architecture allows you to customize your Power Mac G5 to the needs of your workflow-providing tremendous power and productivity in a single system. As your needs change, you'll have the flexibility to add solutions for emerging workflow scenarios, such as HD video and next-generation networking. Modern serial expansion architecture PCI Express is a modern industry standard sponsored by the Peripheral Component Interconnect Special Interest Group (PCI SIG). Because older parallel technologies placed multiple devices on a single bus, the slowest device determined the speed of the entire bus. A serial technology, PCI Express guarantees each device dedicated bandwidth to and from the system controller. PCI Express communicates in 250-MBps "data lanes." PCI Express cards and slots are defined by their bandwidth, or number of data lanes-typically one lane, four lanes, eight lanes, or 16 lanes. At 250 MBps per lane, a four-lane slot can transfer data at up to 1 GBps and an eight-lane slot, up to 2 GBps-approximately twice as fast as a 133MHz PCI-X slot.