PowerPC 970
Encyclopedia
The PowerPC 970, PowerPC 970FX, PowerPC 970GX, and PowerPC 970MP, are 64-bit
Power Architecture
processors
from IBM
introduced in 2002. When used in Apple Inc. machines, they were dubbed the PowerPC G5.
The 970 family was created through a collaboration between IBM and Apple. The project went under the codename GP-UL or Giga Processor Ultra Light, where Giga Processor was the codename for the POWER4
from which the core was derived. When Apple introduced the Power Mac G5 they stated that this was a five year collaborative effort, with multiple future generations, but it was short-lived. Apple had to retract the promise to deliver a 3 GHz processor one year after its introduction and IBM could never get the power consumption down far enough for these processors to fit into a portable computer. Apple only used three variants of the processor.
IBM’s JS20/JS21 blade modules
and some low-end workstation
s and System p servers are based on PowerPC 970. It is also used in some high end embedded systems like Mercury
’s Momentum XSA-200. IBM is also licensing the PowerPC 970 core for use in custom applications. A common misconception is that the PowerPC 970 was the core in IBM
's Xenon
processor in Microsoft
's Xbox 360
, but this is false. That processor is using cores similar to the Power Processing Element (PPE) in the Cell microprocessor
.
The PowerPC 970 is a single core derivative of the POWER4
and can process both 32-bit
and 64-bit
PowerPC instructions natively. It has a hardware prefetch unit
and a three way branch prediction unit
.
Like the POWER4, the front-end is nine stages long. The PowerPC 970 can fetch and decode up to eight instructions, dispatch up to five to reserve stations, issue up to eight to the execution units and retire up to five per cycle. The execution pipelines were lengthened compared to the POWER4 to achieve higher clock frequencies. It has eight execution units: two arithmetic logic unit
s (ALUs), two double precision
floating-point units, two load/store units and two AltiVec
units.
One of the AltiVec units executes integer and floating-point instructions, and the other only permute instructions. The latter has a three subunits for simple integer, complex integer and floating-point instructions. These units have pipelines of varying lengths: 10 stages for simple integer and permute instructions, 13 stages for complex integer instructions and 16 stage for floating-point instructions.
The processor has two unidirectional 32-bit double data rate
(DDR) buses (one for reads, the other for writes) to the system controller chip (northbridge
) running at one quarter of the processor core speed. The buses also carry addresses and control signals in addition to data so only a percentage of the peak bandwidth can be realized (6.4 GB/s at 450 MHz). As the buses are unidirectional, each direction can realize only half the aggregate bandwidth, or 3.2 GB/s.
's Power Mac G5
in June 2003 (in keeping with its previous naming conventions, Apple termed the PowerPC 970 based products G5, for the fifth generation of PowerPC microprocessors). IBM released its first PowerPC 970 blade servers, the BladeCenter JS20
, in November 2003.
The PowerPC 970 had 512 KB of full-speed L2 cache and clock speeds from 1.6 to 2.0 GHz. The front side bus ran at half the processor's clock speed.
Apple released their 970FX-powered machines throughout 2004: the Xserve G5 in January, the Power Mac G5 in June, and the iMac G5
in August. The Power Mac introduced a top clock speed of 2.5 GHz while liquid-cooled
(eventually reaching as high as 2.7 GHz in April 2005). The iMac ran the front side bus at a third of the clock speed.
Despite intense user demand for a faster laptop CPU than the G4, Apple never used a G5 series CPU in their PowerBook
laptops. The original 970 used far too much power and was never seriously viewed as a candidate for a portable computer. The 970FX reduced thermal design power
(TDP) to about 30 W at 1.5 GHz, a figure which led many users to believe a PowerBook G5 might be possible. However, several obstacles prevented even the 970FX from being used in this application. At 1.5 GHz, the G5 was not substantially faster than the 1.5 and 1.67 GHz G4 processors which Apple used in PowerBooks instead. Furthermore, the northbridge chips available to interface the 970FX to memory and other devices were not designed for portable computers, and consumed too much power. Finally, the 970FX had inadequate power saving features for a portable CPU. Its minimum (idle) power was much too high, which would have led to poor battery life figures in a notebook computer.
The PowerPC 970MP replaced the PowerPC 970FX in Apple's high-end Power Mac G5
computers, while the iMac G5
and the legacy PCI-X
Power Mac G5 continued to use the PowerPC 970FX processor. The PowerPC 970MP is used in IBM's JS21 blade modules and IBM Intellistation POWER 185 workstation.
Due to high power requirements IBM has chosen to discontinue parts running faster than 2.0 GHz.
for PowerPC 970-based computers, both manufactured by IBM:
There was also a cancelled CPC965 northbridge. Slated for release in 2007, it was to be a uniprocessor-only northbridge. Its features were a 533 MHz DDR2 controller that supported up to 8 GB ECC memory, a 8x PCIe bus, integrated four-port Gigabit Ethernet
with IPv4
TCP
/UDP
offloading, USB 2.0 ports, a Flash
-interface. The northbridge contains an integrated PowerPC 405 core to provide system management and configuration capabilities.
64-bit
64-bit is a word size that defines certain classes of computer architecture, buses, memory and CPUs, and by extension the software that runs on them. 64-bit CPUs have existed in supercomputers since the 1970s and in RISC-based workstations and servers since the early 1990s...
Power Architecture
Power Architecture
Power Architecture is a broad term to describe similar RISC instruction sets for microprocessors developed and manufactured by such companies as IBM, Freescale, AMCC, Tundra and P.A. Semi...
processors
Central processing unit
The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...
from IBM
IBM
International Business Machines Corporation or IBM is an American multinational technology and consulting corporation headquartered in Armonk, New York, United States. IBM manufactures and sells computer hardware and software, and it offers infrastructure, hosting and consulting services in areas...
introduced in 2002. When used in Apple Inc. machines, they were dubbed the PowerPC G5.
The 970 family was created through a collaboration between IBM and Apple. The project went under the codename GP-UL or Giga Processor Ultra Light, where Giga Processor was the codename for the POWER4
POWER4
The POWER4 is a microprocessor developed by International Business Machines that implemented the 64-bit PowerPC and PowerPC AS instruction set architectures. Released in 2001, the POWER4 succeeded the POWER3 and RS64 microprocessors, and was used in RS/6000 and AS/400 computers, ending a separate...
from which the core was derived. When Apple introduced the Power Mac G5 they stated that this was a five year collaborative effort, with multiple future generations, but it was short-lived. Apple had to retract the promise to deliver a 3 GHz processor one year after its introduction and IBM could never get the power consumption down far enough for these processors to fit into a portable computer. Apple only used three variants of the processor.
IBM’s JS20/JS21 blade modules
Blade server
A blade server is a stripped down server computer with a modular design optimized to minimize the use of physical space and energy. Whereas a standard rack-mount server can function with a power cord and network cable, blade servers have many components removed to save space, minimize power...
and some low-end workstation
Workstation
A workstation is a high-end microcomputer designed for technical or scientific applications. Intended primarily to be used by one person at a time, they are commonly connected to a local area network and run multi-user operating systems...
s and System p servers are based on PowerPC 970. It is also used in some high end embedded systems like Mercury
Mercury Computer Systems
Mercury Computer Systems, Inc. provides high-performance embedded, real-time digital signal and image processing solutions.Mercury designs and builds embedded multicomputers, which may be considered to be either loosely coupled NUMA computers or tightly coupled clusters. Despite being marketed as...
’s Momentum XSA-200. IBM is also licensing the PowerPC 970 core for use in custom applications. A common misconception is that the PowerPC 970 was the core in IBM
IBM
International Business Machines Corporation or IBM is an American multinational technology and consulting corporation headquartered in Armonk, New York, United States. IBM manufactures and sells computer hardware and software, and it offers infrastructure, hosting and consulting services in areas...
's Xenon
Xenon (processor)
Xenon is a CPU that is used in the Xbox 360 game console. The processor, internally codenamed "Waternoose", which was named after Henry J. Waternoose III in Monsters Inc. by IBM and XCPU by Microsoft, is based on IBM's PowerPC instruction set architecture, consisting of three independent processor...
processor in Microsoft
Microsoft
Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...
's Xbox 360
Xbox 360
The Xbox 360 is the second video game console produced by Microsoft and the successor to the Xbox. The Xbox 360 competes with Sony's PlayStation 3 and Nintendo's Wii as part of the seventh generation of video game consoles...
, but this is false. That processor is using cores similar to the Power Processing Element (PPE) in the Cell microprocessor
Cell microprocessor
Cell is a microprocessor architecture jointly developed by Sony, Sony Computer Entertainment, Toshiba, and IBM, an alliance known as "STI". The architectural design and first implementation were carried out at the STI Design Center in Austin, Texas over a four-year period beginning March 2001 on a...
.
Design
POWER4
The POWER4 is a microprocessor developed by International Business Machines that implemented the 64-bit PowerPC and PowerPC AS instruction set architectures. Released in 2001, the POWER4 succeeded the POWER3 and RS64 microprocessors, and was used in RS/6000 and AS/400 computers, ending a separate...
and can process both 32-bit
32-bit
The range of integer values that can be stored in 32 bits is 0 through 4,294,967,295. Hence, a processor with 32-bit memory addresses can directly access 4 GB of byte-addressable memory....
and 64-bit
64-bit
64-bit is a word size that defines certain classes of computer architecture, buses, memory and CPUs, and by extension the software that runs on them. 64-bit CPUs have existed in supercomputers since the 1970s and in RISC-based workstations and servers since the early 1990s...
PowerPC instructions natively. It has a hardware prefetch unit
Instruction prefetch
In computer architecture, instruction prefetch is a technique used in microprocessors to speed up the execution of a program by reducing wait states....
and a three way branch prediction unit
Branch predictor
In computer architecture, a branch predictor is a digital circuit that tries to guess which way a branch will go before this is known for sure. The purpose of the branch predictor is to improve the flow in the instruction pipeline...
.
Like the POWER4, the front-end is nine stages long. The PowerPC 970 can fetch and decode up to eight instructions, dispatch up to five to reserve stations, issue up to eight to the execution units and retire up to five per cycle. The execution pipelines were lengthened compared to the POWER4 to achieve higher clock frequencies. It has eight execution units: two arithmetic logic unit
Arithmetic logic unit
In computing, an arithmetic logic unit is a digital circuit that performs arithmetic and logical operations.The ALU is a fundamental building block of the central processing unit of a computer, and even the simplest microprocessors contain one for purposes such as maintaining timers...
s (ALUs), two double precision
Double precision
In computing, double precision is a computer number format that occupies two adjacent storage locations in computer memory. A double-precision number, sometimes simply called a double, may be defined to be an integer, fixed point, or floating point .Modern computers with 32-bit storage locations...
floating-point units, two load/store units and two AltiVec
AltiVec
AltiVec is a floating point and integer SIMD instruction set designed and owned by Apple, IBM and Freescale Semiconductor, formerly the Semiconductor Products Sector of Motorola, , and implemented on versions of the PowerPC including Motorola's G4, IBM's G5 and POWER6 processors, and P.A. Semi's...
units.
One of the AltiVec units executes integer and floating-point instructions, and the other only permute instructions. The latter has a three subunits for simple integer, complex integer and floating-point instructions. These units have pipelines of varying lengths: 10 stages for simple integer and permute instructions, 13 stages for complex integer instructions and 16 stage for floating-point instructions.
The processor has two unidirectional 32-bit double data rate
Double data rate
In computing, a computer bus operating with double data rate transfers data on both the rising and falling edges of the clock signal. This is also known as double pumped, dual-pumped, and double transition....
(DDR) buses (one for reads, the other for writes) to the system controller chip (northbridge
Northbridge (computing)
The northbridge has historically been one of the two chips in the core logic chipset on a PC motherboard, the other being the southbridge. Increasingly these functions have migrated to the CPU chip itself, beginning with memory and graphics controllers. For Intel Sandy Bridge and AMD Fusion...
) running at one quarter of the processor core speed. The buses also carry addresses and control signals in addition to data so only a percentage of the peak bandwidth can be realized (6.4 GB/s at 450 MHz). As the buses are unidirectional, each direction can realize only half the aggregate bandwidth, or 3.2 GB/s.
PowerPC 970
The PowerPC 970 was announced by IBM in October 2002. It was released in Apple ComputerApple Computer
Apple Inc. is an American multinational corporation that designs and markets consumer electronics, computer software, and personal computers. The company's best-known hardware products include the Macintosh line of computers, the iPod, the iPhone and the iPad...
's Power Mac G5
Power Mac G5
The Power Mac G5 is Apple's marketing name for models of the Power Macintosh that contains the IBM PowerPC G5 CPU. The professional-grade computer was the most powerful in Apple's lineup when it was introduced, widely hailed as the first 64-bit PC, and was touted by Apple as the fastest personal...
in June 2003 (in keeping with its previous naming conventions, Apple termed the PowerPC 970 based products G5, for the fifth generation of PowerPC microprocessors). IBM released its first PowerPC 970 blade servers, the BladeCenter JS20
IBM BladeCenter
The IBM BladeCenter is IBM's blade server architecture.-History:Originally introduced in 2002, based on engineering work started in 1999, the IBM BladeCenter was a relative late comer to the blade market. But, it differed from prior offerings in that it supported the full range of high powered x86...
, in November 2003.
The PowerPC 970 had 512 KB of full-speed L2 cache and clock speeds from 1.6 to 2.0 GHz. The front side bus ran at half the processor's clock speed.
PowerPC 970FX
The PowerPC 970FX used a 90 nm manufacturing process and has a maximum power rating of 11 watts at 149 degrees Fahrenheit (65 °C) while clocked at 1 GHz and a maximum of 48 watts at 2 GHz.Apple released their 970FX-powered machines throughout 2004: the Xserve G5 in January, the Power Mac G5 in June, and the iMac G5
IMac G5
The iMac G5 was a series of desktop Macintosh computers designed and built by Apple Inc. using the PowerPC chip architecture. It was the last line of iMac computers that used a PowerPC chip, making it the last of the iMacs that could run Mac OS 9 applications. In August 2004, the iMac design was...
in August. The Power Mac introduced a top clock speed of 2.5 GHz while liquid-cooled
Computer cooling
Computer cooling is required to remove the waste heat produced by computer components, to keep components within their safe operating temperature limits.Various cooling methods help to improve processor performance or reduce the noise of cooling fans....
(eventually reaching as high as 2.7 GHz in April 2005). The iMac ran the front side bus at a third of the clock speed.
Despite intense user demand for a faster laptop CPU than the G4, Apple never used a G5 series CPU in their PowerBook
PowerBook
The PowerBook was a line of Macintosh laptop computers that was designed, manufactured and sold by Apple Computer, Inc. from 1991 to 2006. During its lifetime, the PowerBook went through several major revisions and redesigns, often being the first to incorporate features that would later become...
laptops. The original 970 used far too much power and was never seriously viewed as a candidate for a portable computer. The 970FX reduced thermal design power
Thermal Design Power
The thermal design power , sometimes called thermal design point, refers to the maximum amount of power the cooling system in a computer is required to dissipate. For example, a laptop's CPU cooling system may be designed for a 20 watt TDP, which means that it can dissipate up to 20 watts of heat...
(TDP) to about 30 W at 1.5 GHz, a figure which led many users to believe a PowerBook G5 might be possible. However, several obstacles prevented even the 970FX from being used in this application. At 1.5 GHz, the G5 was not substantially faster than the 1.5 and 1.67 GHz G4 processors which Apple used in PowerBooks instead. Furthermore, the northbridge chips available to interface the 970FX to memory and other devices were not designed for portable computers, and consumed too much power. Finally, the 970FX had inadequate power saving features for a portable CPU. Its minimum (idle) power was much too high, which would have led to poor battery life figures in a notebook computer.
PowerPC 970MP
IBM announced the PowerPC 970MP, code-named "Antares", on 7 July 2005 at the Power Everywhere forum in Tokyo. The 970MP is a dual-core derivative of the 970FX with clock speeds between 1.2 and 2.5 GHz, and a maximum power usage of 75 W at 1.8 GHz and 100 W at 2.0 GHz. Each core has 1 MB of L2 cache, twice that of the 970FX. Like the 970FX, this chip was produced at the 90 nm process. When one of the cores is idle, it will enter a "doze" state and shut down. The 970MP also includes partitioning and virtualization features.The PowerPC 970MP replaced the PowerPC 970FX in Apple's high-end Power Mac G5
Power Mac G5
The Power Mac G5 is Apple's marketing name for models of the Power Macintosh that contains the IBM PowerPC G5 CPU. The professional-grade computer was the most powerful in Apple's lineup when it was introduced, widely hailed as the first 64-bit PC, and was touted by Apple as the fastest personal...
computers, while the iMac G5
IMac
The iMac is a range of all-in-one Macintosh desktop computers built by Apple. It has been the primary part of Apple's consumer desktop offerings since its introduction in 1998, and has evolved through five distinct forms....
and the legacy PCI-X
PCI-X
PCI-X, short for PCI-eXtended, is a computer bus and expansion card standard that enhances the 32-bit PCI Local Bus for higher bandwidth demanded by servers. It is a double-wide version of PCI, running at up to four times the clock speed, but is otherwise similar in electrical implementation and...
Power Mac G5 continued to use the PowerPC 970FX processor. The PowerPC 970MP is used in IBM's JS21 blade modules and IBM Intellistation POWER 185 workstation.
Due to high power requirements IBM has chosen to discontinue parts running faster than 2.0 GHz.
PowerPC 970GX
The PowerPC 970GX is a cancelled single-core version of PowerPC 970MP. It featured a 1 MB L2 cache and would have been available in frequencies of 1.2 to 3 GHz. Power dissipation would have been 16 W at 1.6 GHz, and 85 W at 3 GHz. It was to be fabricated in the same 90 nm fabrication process as the 970MP.Northbridges
There are two dedicated northbridgesNorthbridge (computing)
The northbridge has historically been one of the two chips in the core logic chipset on a PC motherboard, the other being the southbridge. Increasingly these functions have migrated to the CPU chip itself, beginning with memory and graphics controllers. For Intel Sandy Bridge and AMD Fusion...
for PowerPC 970-based computers, both manufactured by IBM:
- CPC925 — Designed by Apple and called the U3 or the U3H (which supports ECC memory). It is capable of supporting up to two PowerPC 970s or PowerPC 970FXs and has two 550 MHz unidirectional processor buses, a 400 MHz DDRDDR SDRAMDouble data rate synchronous dynamic random access memory is a class of memory integrated circuits used in computers. DDR SDRAM has been superseded by DDR2 SDRAM and DDR3 SDRAM, neither of which are either forward or backward compatible with DDR SDRAM, meaning that DDR2 or DDR3 memory modules...
memory controller, x8 AGPAccelerated Graphics PortThe Accelerated Graphics Port is a high-speed point-to-point channel for attaching a video card to a computer's motherboard, primarily to assist in the acceleration of 3D computer graphics. Since 2004 AGP has been progressively phased out in favor of PCI Express...
and a 400 MHz 16-bit HyperTransportHyperTransportHyperTransport , formerly known as Lightning Data Transport , is a technology for interconnection of computer processors. It is a bidirectional serial/parallel high-bandwidth, low-latency point-to-point link that was introduced on April 2, 2001...
tunnel. It fabricated on a 130 nm process.
- CPC945 — Designed by IBM and called U4 by Apple, it is capable of supporting two PowerPC 970MPs and has two 625 MHz unidirectional processor buses, two memory controllers that support up to 64 GB of 533 MHz DDR2 SDRAM with ECC capability and has a x16 PCIe lane and an 800 MHz 16-bit HyperTransport tunnel. It is fabricated on a 90 nm process.
There was also a cancelled CPC965 northbridge. Slated for release in 2007, it was to be a uniprocessor-only northbridge. Its features were a 533 MHz DDR2 controller that supported up to 8 GB ECC memory, a 8x PCIe bus, integrated four-port Gigabit Ethernet
Gigabit Ethernet
Gigabit Ethernet is a term describing various technologies for transmitting Ethernet frames at a rate of a gigabit per second , as defined by the IEEE 802.3-2008 standard. It came into use beginning in 1999, gradually supplanting Fast Ethernet in wired local networks where it performed...
with IPv4
IPv4
Internet Protocol version 4 is the fourth revision in the development of the Internet Protocol and the first version of the protocol to be widely deployed. Together with IPv6, it is at the core of standards-based internetworking methods of the Internet...
TCP
Transmission Control Protocol
The Transmission Control Protocol is one of the core protocols of the Internet Protocol Suite. TCP is one of the two original components of the suite, complementing the Internet Protocol , and therefore the entire suite is commonly referred to as TCP/IP...
/UDP
User Datagram Protocol
The User Datagram Protocol is one of the core members of the Internet Protocol Suite, the set of network protocols used for the Internet. With UDP, computer applications can send messages, in this case referred to as datagrams, to other hosts on an Internet Protocol network without requiring...
offloading, USB 2.0 ports, a Flash
Flash memory
Flash memory is a non-volatile computer storage chip that can be electrically erased and reprogrammed. It was developed from EEPROM and must be erased in fairly large blocks before these can be rewritten with new data...
-interface. The northbridge contains an integrated PowerPC 405 core to provide system management and configuration capabilities.
See also
- POWER3POWER3The POWER3 is a microprocessor, designed and exclusively manufactured by IBM, that implemented the 64-bit version of the PowerPC instruction set architecture , including all of the optional instructions of the ISA such as the POWER2. It was introduced on 5 October 1998, debuting in the RS/6000 43P...
, POWER4POWER4The POWER4 is a microprocessor developed by International Business Machines that implemented the 64-bit PowerPC and PowerPC AS instruction set architectures. Released in 2001, the POWER4 succeeded the POWER3 and RS64 microprocessors, and was used in RS/6000 and AS/400 computers, ending a separate...
and POWER5POWER5The POWER5 is a microprocessor developed and fabricated by IBM. It is an improved version of the highly successful POWER4. The principal improvements are support for simultaneous multithreading and an on-die memory controller... - PowerPC G4PowerPC G4PowerPC G4 is a designation used by Apple Computer to describe a fourth generation of 32-bit PowerPC microprocessors. Apple has applied this name to various processor models from Freescale, a former part of Motorola....
and AltivecAltiVecAltiVec is a floating point and integer SIMD instruction set designed and owned by Apple, IBM and Freescale Semiconductor, formerly the Semiconductor Products Sector of Motorola, , and implemented on versions of the PowerPC including Motorola's G4, IBM's G5 and POWER6 processors, and P.A. Semi's... - Power Mac G5Power Mac G5The Power Mac G5 is Apple's marketing name for models of the Power Macintosh that contains the IBM PowerPC G5 CPU. The professional-grade computer was the most powerful in Apple's lineup when it was introduced, widely hailed as the first 64-bit PC, and was touted by Apple as the fastest personal...
and Xserve G5 - Supercomputers using the PowerPC 970:
- System XSystem X (computing)System X is a supercomputer assembled by Virginia Tech's Advanced Research Computing facility in the summer of 2003 that was originally composed of 1,100 Apple Power Mac G5 computers. System X ran at 12.25 Teraflops, , and was ranked #3 on November 16, 2003 and #280 in the July 2008 edition of...
- All supercomputers in Spanish Supercomputing NetworkSpanish Supercomputing NetworkThe Spanish Supercomputing Network is a scientific network created by the Spanish Education Ministry. The network is composed by several supercomputers distributed over Spain...
(MageritMageritMagerit is the name of the one of the most powerful supercomputers of Spain. It also reached the second best Spanish position in the TOP500 list of supercomputers.This computer is installed in CeSViMa, a research center of the Technical University of Madrid....
and MarenostrumMareNostrumMareNostrum is a supercomputer in the Barcelona Supercomputing Center, the second most powerful in Spain. It was presented by IBM and María Jesús San Segundo, the Spanish Minister of Education and Science...
are the two most powerful supercomputers of the network)
- System X
Further reading
- "IBM's PPC970 Becomes Apple's G5". (7 July 2003). Microprocessor Report.
- "IBM Takes the Lead". (9 February 2004). Microprocessor Report.
- "IBM's Double-Shot of PowerPC". (7 November 2005). Microprocessor Report.