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Overview to the Single Processor Power Mac G5
The single processor, 64-bit desktop Power Mac G5 uses a PowerPC G5 processor and is intended for use in content creation, desktop publishing, multimedia, scientific and technical applications, and other activities that require high performance.
New Hardware Features
Here is a list of the new hardware features of the single processor Power Mac G5. A list of all hardware features is provided in Hardware Features Summary.
Microprocessor: The single processor Power Mac G5 has a 1.8 GHz PowerPC G5 processor. For more information, see PowerPC G5 Processor.
Processor system bus: The processor interface system bus runs at one-third the speed of the system processor. For more information, see Processor Bus.
Memory bus: The main memory bus is 128 bit 400 MHz. For more information, see Main Memory Bus.
DDR SDRAM: The computer has four DIMM slots for 184 pin DIMMs (dual inline memory modules) using unbuffered DDR (double data rate) SDRAM 64-bit, 400 MHz (PC3200) devices for a maximum of 4 GB. For more information, see Main Memory Bus.
Graphics card: The computer comes standard with the Nvidia GeForce Fx 5200 Ultra with 64 MB RAM. Available as build-to-order options are the ATI Radeon 9800 XT with 256 MB RAM, the ATI Radeon 9600 XT with 128 MB RAM, the Nvidia GeForce 6800 Ultra DDL with 256 MB RAM, and the Nvidia GeForce 6800 GT DDL with 256 MB RAM. For more information, see Graphics Cards.
Hard disks: An internal 7200 rpm Serial ATA (SATA) hard disk occupies one of two drive bays and functions as the default boot disk. A second SATA drive is available as a build-to-order option. The single processor Power Mac G5 comes standard with an 80GB SATA hard drive, and 160GB and 250GB SATA drives are available as build-to-order options For more information, see Serial ATA Interface.
Hardware Features Summary
Here is a list of the hardware features of the single processor Power Mac G5. The major features are described more fully later in this note. To view technical Marketing documents, refer to http://www.apple.com/powermac/.
Microprocessor: The single processor Power Mac G5 computer has a 1.8 GHz PowerPC G5 processor. For more information, see PowerPC G5 Processor.
Processor system bus: The processor interface system bus runs at one-third the speed of the system processor. For more information, see Processor Bus.
Memory caches: The PowerPC G5 microprocessor used in the computer has an internal 512 KB level 2 cache.
Memory bus: The main memory bus is 128 bit 400 MHz. For more information, see Main Memory Bus.
DDR SDRAM: The computer has four DIMM slots for 184 pin DIMMs (dual inline memory modules) using unbuffered DDR (double data rate) SDRAM 64-bit, 400 MHz (PC3200) devices for a maximum of 4 GB. For more information, see Main Memory Bus.
AGP 8x Pro card slot: The computer has an AGP 3.0 8x Pro accelerated graphics card installed in this slot. For more information, see Accelerated Graphics Port Bus.
PCI expansion slots: The computer supports three 64-bit 33 MHz PCI slots. For more information, see PCI Expansion Slots.
Hyper Transport bus: The computer supports the high-speed bus architecture between the memory controller and device I/O. For more information, see HyperTransport Technology.
Graphics card: The computer comes standard with the Nvidia GeForce Fx 5200 Ultra with 64 MB RAM. Available as build-to-order options are the ATI Radeon 9800 XT with 256 MB RAM, the ATI Radeon 9600 XT with 128 MB RAM, the Nvidia GeForce 6800 Ultra DDL with 256 MB RAM, and the Nvidia GeForce 6800 GT DDL with 256 MB RAM. For more information, see Graphics Cards.
Hard disks: An internal 7200 rpm Serial ATA (SATA) hard disk occupies one of two drive bays and functions as the default boot disk. A second SATA drive is available as a build-to-order option. The single processor Power Mac G5 comes standard with an 80GB SATA hard drive, and 160GB and 250GB SATA drives are available as build-to-order options. For more information, see Serial ATA Interface.
SuperDrive: The computer has a SuperDrive (DVD-R/CD-RW drive) connected to the Ultra DMA ATA/100 bus. For more information, see SuperDrive.
Combo drive: Instead of a SuperDrive, the computer has an optional build-to-order combination DVD-ROM/CD-RW drive connected to the Ultra DMA ATA/100 bus. For more information, see Combo Drive.
High-speed USB 2.0: The computer has three external USB 2.0 ports: two on the rear of the enclosure and one on the front. All ports support both high-speed and classic USB speeds. For more information, see USB Ports.
Ethernet: The computer has a built-in Ethernet port for 10Base-T/UTP, 100Base-TX, or 1000Base-TX Gigabit operation. The Ethernet port is auto-sensing and self-configuring to allow use of either a cross-over or straight-through cable. For more information, see Ethernet Port.
AirPort Extreme Card: Available as a build-to-order option, the 54 Mbps AirPort Extreme Card provides a wireless LAN connection. For more information, see Wireless LAN Module.
Bluetooth: Available as a build-to-order option, the fully-integrated Bluetooth module enables short-range wireless connections between desktop and laptop computers and a host of other peripheral devices. For more information, see Bluetooth Technology.
FireWire ports: The computer has two FireWire 400 ports and one FireWire 800 port. For more information, see FireWire Controllers.
Modem: The computer has a built-in Apple 56 Kbps modem. The modem supports K56flex and V.90 and V.92 modem standards. For more information, see Internal Modem.
Keyboard: The computer comes with a full-size USB Apple Keyboard. The keyboard is also a bus-powered USB hub with two USB ports. For more information, see Keyboard.
Mouse: The computer comes with a USB Apple Mouse, with optical tracking. For more information, see Mouse.
Boot ROM: The computer comes with 1 MB of boot ROM.
S/PDIF digital audio: The computer implements S/PDIF (Sony/Phillips Digital Interface) digital audio I/O via TOSLink optical input and digital output connectors on the rear panel. For more information, see Sound System Overview.
Analog audio line-in: Rear panel analog audio line-in port for self-powered microphones or other audio equipment. For more information, see Audio Line-in.
Analog audio line-out: Rear panel analog audio line-out port for externally-powered speakers or other audio devices with line-level outputs. For more information, see Audio Line-out.
Headphone and internal speaker: The front panel includes a headphone mini-jack and the system includes a front mono speaker. For more information, see Headphone Jack.
DVI to video adapter: The computer supports S-video and composite video from an optional adapter connected to the DVI port. For more information, see DVI to Video Adapter.
Voltage switching: Auto-ranging voltage switching accepts 100 - 240V.
Fan speed control: The speeds of the fans are controlled by thermal/wattage factors and are automatically set as low as possible to minimize noise.
Dimensions and weight: The dimensions of the single processor Power Mac G5 are 20.12” (511 mm) high by 8.11” (206 mm) wide by 18.70” (475 mm) deep and weighs approximately 36 pounds.
Energy saving: Processor performance can be set to automatic (default), highest, or reduced via the Energy Saver pane in System Preferences. See Power Management for more detail.
Features of the Enclosure
The single processor Power Mac G5 computer’s enclosure is a tower design. Figure 1-1 illustrates the front of the enclosure and Figure 1-2 illustrates the rear of the enclosure.
The enclosure has space for two hard disk drives and one optical device. See Hard Disk Drives.
To access the main logic board to install PCI cards or additional memory, refer to Expansion. For full details regarding opening and accessing the computer, refer to the Power Mac G5 User’s Guide that was shipped with your computer.
System Software
The single processor Power Mac G5 computer ships with Mac OS X 10.3.5 installed as the default operating system. The classic environment can be used to run Mac OS 9 applications. Install the Classic application from the “Additional Software and Apple Hardware Test” CD shipped with your computer.
To retrieve information from the I/O Registry, use the APIs in the header file IOKit/IOKitLib.h.
Computer Identification
Rather than reading the box flag or the model string and then making assumptions about the computer’s features, applications that need to find out the features of the computer should use I/O Registry calls to test for the features they require.
Asset management software that reports the kind of computer it is run on can obtain the value of the property at Devices:device-tree:compatible in the IODeviceTree plane of the I/O Registry. The model string is the first program-usable string in the array of C strings in the compatible field. For the single processor Power Mac G5, the value of the model property is PowerMac9,1.
Power Management
The power management techniques implemented in the single processor Power Mac G5 are described in the following paragraphs.
Processor Power Step
To lower power consumption, heat generation, and fan noise, the single processor Power Mac G5 computer incorporates an automatic power management technique called power stepping. Power stepping is designed to run at high processor and bus speeds and high voltage when the demand on the processor is high, and to run at low processor and bus speeds and low voltage when the demand on the processor is low. The stepped processor speed is either 900 MHz or 1.8 GHz. Switching between different processor/bus speeds and voltages is achieved by a very fast transition that is designed to minimally impact system or application performance and typically operates seamlessly to the user.
In addition, the single processor Power Mac G5 computer allows the user to control processor and bus. The options for specifying either high, reduced, or automatic processor and bus speeds are located at System Preferences>Energy Saver>Options; then select Automatic (default), Highest, or Reduced.
If the single processor Power Mac G5 computer detects a system temperature that is too high, due to high ambient temperatures or other factors, it will automatically reduce the processor and bus speeds to half speed, regardless of the selected setting. If the temperature continues to be too high, the system will enter sleep mode to prevent permanent damage.
Processor States
The following processor states are defined:
Run: The system is running at maximum processing capacity with the processor running at full speed.
Idle: The system is idling; this is the default state. All clocks are running and the system can return to running code within a few nanoseconds. If the system has no work to do, it will be in idle mode.
From idle, the processor will enter deep nap state when the system is power-stepped to half frequency. In this state, the processor’s internal frequency is reduced to 1/64 of the maximum frequency. The processor frequency is returned to normal on exit from idle. The exit from idle takes a bit longer than the regular idle nap but is still in the nanoseconds.
System Modes
The Macintosh system has the following power-saving modes, which are set in the Energy Saver pane. If the system does not support full sleep, it will use the less efficient doze mode.
Run: The system is fully functional in normal operating mode with all components powered and operating.
Doze (default): The power to the disk drive motors and the display is turned off, but the power supply and fans are still on. PCI cards that don't support full system sleep (some SCSI cards, some graphics cards) will cause the machine to doze rather than fully sleep.
Full sleep: The main power supply is shut down. A trickle supply provides auxiliary power to the PCI slots and keeps the DRAM state preserved for a quick recovery. The processor is powered off with its state preserved in DRAM. All non-essential clocks in the system are suspended. This mode allows the computer to meet Energy Star sleep requirements while providing the ability to start up without rebooting. This system may be awakened by administrative network packets, keyboard or mouse activity, USB device insertion or removal, or SMU scheduled wakeup.
Off: The single processor Power Mac G5 meets FEMP (Federal Energy Management Program) requirements and supports FireWire ports functioning as repeaters when operating on AC power.
Velocity Engine Acceleration
The Velocity Engine is the vector processing unit in the PowerPC G5 microprocessor. System software has been modified to take advantage of the accelerated processing that the Velocity Engine makes possible and to support low-level operations using the Velocity Engine.
For complete information on the Velocity Engine, refer to the following Apple website:
Copyright © 2003, 2004 Apple Computer, Inc. All Rights Reserved. Terms of Use | Privacy Policy | Updated: 2004-10-19