Editing PowerPC 970

{{Short description|64-bit processor}}
{{Use mdy dates|date=November 2023}}
{{Infobox CPU
| name           = PowerPC 970
| image          = PowerPC-970.jpg
| caption        = Artist's rendering of a PowerPC 970 CPU
| produced-start = 2002
| produced-end   =
| slowest        = 1.0&nbsp;GHz
| slow-unit      =
| fastest        = 2.7&nbsp;GHz
| fast-unit      =
| size-from      = [[130 nanometer|130 nm]]
| size-to        = [[90 nanometer|90 nm]]
| soldby         =
| designfirm     = [[IBM]]
| manuf1         = [[IBM]]
| arch           = 32/64-bit [[PowerPC|PowerPC 2.01]]
| microarch      = ppc970, [[POWER4]]
| transistors    =
| numcores       = 1-2
| l1cache        = 64&nbsp;KB instruction<br/>32&nbsp;KB data
| l2cache        = 512–1024&nbsp;KB
| l3cache        =
| application    = Desktop
| gpu            =
| variant        = 970, 970FX, 970MP
| predecessor    = [[POWER4]]
| successor      =
}}
{{POWER, PowerPC, and Power ISA}}
The '''PowerPC 970''', '''PowerPC 970FX''', and '''PowerPC 970MP''' are [[64-bit]] [[PowerPC]] [[central processing unit|CPUs]] from [[IBM]] introduced in 2002. [[Apple Inc.|Apple]] branded the 970 as '''PowerPC G5''' for its [[Power Mac G5]].

Having created the PowerPC architecture in the early 1990s via the [[AIM alliance]], the 970 family was created through a further collaboration between IBM and [[Apple Inc.|Apple]].<ref>{{cite web |url=https://www.apple.com/newsroom/2003/06/23Apple-Unleashes-the-Worlds-Fastest-Personal-Computer-the-Power-Mac-G5/ |title=Apple Unleashes the World's Fastest Personal Computer—the Power Mac G5 |date=June 23, 2003 |publisher=Apple |access-date=December 4, 2017 |archive-date=December 16, 2021 |archive-url=https://web.archive.org/web/20211216111135/https://www.apple.com/newsroom/2003/06/23Apple-Unleashes-the-Worlds-Fastest-Personal-Computer-the-Power-Mac-G5/ |url-status=live }}</ref><ref>{{cite web |url=https://www.apple.com/newsroom/2003/06/23Apple-and-IBM-Introduce-the-PowerPC-G5-Processor/ |title=Apple and IBM Introduce the PowerPC G5 Processor |publisher=Apple |date=June 23, 2003 |access-date=December 4, 2017 |archive-date=April 21, 2022 |archive-url=https://web.archive.org/web/20220421214222/https://www.apple.com/newsroom/2003/06/23Apple-and-IBM-Introduce-the-PowerPC-G5-Processor/ |url-status=live }}</ref> The project was [[codename]]d GP-UL or Giga Processor Ultra Light, where Giga Processor is the codename for the [[POWER4]] from which the core was derived. When Apple introduced the [[Power Mac G5]], it stated that this was a five-year collaborative effort, with multi-generation roadmap. This forecast however was short-lived when Apple later had to retract its promise to deliver a 3&nbsp;GHz processor only one year after its introduction. IBM was also unable to reduce power consumption to levels necessary for laptop computers. Ultimately, Apple only used three variants of the processor.

IBM's JS20/JS21 [[blade server|blade modules]] and some low-end [[workstation]]s and [[System p]] servers are based on the PowerPC 970. It is also used in some high end embedded systems like [[Mercury Systems|Mercury]]'s Momentum XSA-200. IBM is also licensing the PowerPC 970 core for use in custom applications.

==Design==
[[File:PPC-970fx.jpg|thumb|PowerPC 970FX processor]]
The PowerPC 970 is a single core derivative of the [[POWER4]] and can process both [[32-bit]] and [[64-bit]] PowerPC [[instruction (computer science)|instruction]]s natively. It has a hardware [[Instruction prefetch|prefetch unit]] and a three way [[Branch predictor|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 [[Instructions per cycle|IPC]]. It has eight execution units: two [[arithmetic logic unit]]s (ALUs), two [[double-precision floating-point format|double-precision]] [[floating-point unit]]s, two load/store units and two [[AltiVec]] units.<ref name="MPR:2002-10-28">Halfhill, Tom R. (October 28, 2002). "IBM Trims Power4, Adds AltiVec". ''[[Microprocessor Report]]''.</ref>

One of the AltiVec units executes integer and floating-point instructions, and the other only permute instructions. The latter has 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.<ref name="MPR:2002-10-28"/>

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 (computing)|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&nbsp;GB/s at 450&nbsp;MHz). As the buses are unidirectional, each direction can realize only half the aggregate bandwidth, or 3.2&nbsp;GB/s.<ref name="MPR:2002-10-28"/>

==Generations==
All generations of 970 processors were manufactured in IBM's East Fishkill plant in New York on a white ceramic substrate that was typical for IBM's high end processors of the era.
{{multiple image
|direction=vertical
|image1=PowerPC-970.jpg
|caption1=The first PowerPC 970 was manufactured on a 130&nbsp;nm process in week 20 of 2003.<ref name="IBMProductionDates">{{Cite web |url=http://www.cpu-world.com/forum/viewtopic.php?t=12736 |title=IBM production dates CPU-World |access-date=2 March 2013 |archive-date=20 April 2018 |archive-url=https://web.archive.org/web/20180420135701/http://www.cpu-world.com/forum/viewtopic.php?t=12736 |url-status=live }}</ref>
|image2=PowerPC-970FX.jpg
|caption2=The PowerPC 970FX was manufactured on a 90&nbsp;nm process in week 25 of 2004,<ref name="IBMProductionDates" /> with the smaller die.
|image3=PowerPC-970MP.jpg
|caption3=The PowerPC 970MP has two cores on the same die and twice the L2 cache per core than the 970FX so its size is much larger. It was manufactured in week 24 of 2005.<ref name="IBMProductionDates" />
}}
===PowerPC 970===
The '''PowerPC 970''' was announced by IBM in October 2002. It was released in [[Apple Inc.|Apple Computer]]'s [[Power Mac G5]] in June 2003. Like its naming convention of G3 and G4, Apple branded the PowerPC 970 based products as G5, for the fifth generation of PowerPC. IBM released its first PowerPC 970 blade servers, the [[IBM BladeCenter|BladeCenter JS20]], in November 2003.

The PowerPC 970 has 512&nbsp;KB of full-speed [[L2 cache]] and clock speeds from 1.6 to 2.0&nbsp;GHz. The front side bus runs at half the processor's clock speed.

===PowerPC 970FX===
The '''PowerPC 970FX''' has a [[90 nanometer|90&nbsp;nm]] manufacturing process and has a maximum power rating of 11 watts at 149 degrees Fahrenheit (65&nbsp;°C) while clocked at 1&nbsp;GHz and a maximum of 48 watts at 2&nbsp;GHz.<ref>{{cite web|url=https://www-01.ibm.com/chips/techlib/techlib.nsf/techdocs/1DE505664D202D2987256D9C006B90A5/$file/PPC970FX_DS_DD3.X_V2.5_26MAR2007_pub.pdf |title=IBM PowerPC 970FX RISC Microprocessor Datasheet |publisher=01.ibm.com |access-date=November 2, 2010}}</ref>

It has 10 functional units{{snd}} 2 Fixed-Point Units, 2 Load/Store Units, 2 Floating Point Units, 1 Branch Unit, 1 SIMD ALU unit, 1 SIMD Permute unit, and 1 Condition Register. It supports up to 215 instructions in-flight: 16 in the Instruction Fetch Unit, 67 in the Instruction Decode Unit, 100 in the Functional Units, and 32 in the Store Queue. It has 64&nbsp;KBs of directly mapped Instruction Cache and 32&nbsp;KBs of D-Cache.<ref>{{cite web |url=https://www-01.ibm.com/chips/techlib/techlib.nsf/techdocs/DC3D43B729FDAD2C00257419006FB955/$file/970FX_user_manual.v1.7.2008MAR14_pub.pdf |title=IBM PowerPC 970FX RISC Microprocessor User's Manual V 1.7 |publisher=www-01.ibm.com |access-date=May 21, 2014 |archive-date=May 22, 2014 |archive-url=https://web.archive.org/web/20140522012345/https://www-01.ibm.com/chips/techlib/techlib.nsf/techdocs/DC3D43B729FDAD2C00257419006FB955/$file/970FX_user_manual.v1.7.2008MAR14_pub.pdf |url-status=live }}</ref>

Apple released 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&nbsp;GHz while [[computer cooling|liquid-cooled]] (eventually reaching as high as 2.7&nbsp;GHz in April 2005). The iMac ran the front side bus at a third of the clock speed.

Market demand was intense for a faster laptop CPU than the G4, but Apple never delivered a G5 series CPU in [[PowerBook]] laptops. The original 970 uses 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 [[Watt (unit)|W]] at 1.5&nbsp;GHz, 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&nbsp;GHz, the G5 was not substantially faster than the 1.5 and 1.67&nbsp;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.{{citation needed|date=November 2010}}

===PowerPC 970MP===
IBM announced the '''PowerPC 970MP''', [[codename]]d "Antares", on July 7, 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&nbsp;GHz, and a maximum power usage of 75&nbsp;W at 1.8&nbsp;GHz and 100&nbsp;W at 2.0&nbsp;GHz. Each core has 1&nbsp;MB of [[L2 cache]], twice that of the 970FX. Like the 970FX, this chip was produced at the 90&nbsp;nm process. When one of the cores is idle, it will enter a "doze" state and shut down.<ref>{{cite web|url=http://www.theinquirer.net/default.aspx?article=24486 |archive-url=https://web.archive.org/web/20060812000943/http://www.theinquirer.net/default.aspx?article=24486 |url-status=unfit |archive-date=August 12, 2006 |title=IBM introduces dual-core PowerPC 970 chip – The INQUIRER |publisher=Theinquirer.net |author=Paul Hales: Friday, July 8, 2005, 5:28 PM |date= July 8, 2005|access-date=September 22, 2008}}</ref> The 970MP also includes partitioning and virtualization features.<ref>{{cite web|url=http://news.zdnet.com/2100-9584_22-5499954.html |title=Next IBM-Apple chip getting high-end feature |publisher=[[ZDNet]] |access-date=September 22, 2008 |archive-url = https://web.archive.org/web/20080417003411/http://news.zdnet.com/2100-9584_22-5499954.html <!-- Bot retrieved archive --> |archive-date = April 17, 2008}}</ref><ref>{{cite web |url=http://www-03.ibm.com/systems/bladecenter/js21e/index.html |title=IBM BladeCenter JS21 Express |publisher=03.ibm.com |access-date=September 22, 2008 |archive-date=September 10, 2007 |archive-url=https://web.archive.org/web/20070910193100/http://www-03.ibm.com/systems/bladecenter/js21e/index.html |url-status=dead }}</ref>

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, IBM Intellistation POWER 185 workstation and YDL PowerStation by [[Fixstars Solutions]] (Yellow Dog Linux (YDL) PowerStation).

Due to high power requirements, IBM discontinued units above 2.0&nbsp;GHz.

==Northbridges==
Two dedicated [[Northbridge (computing)|northbridges]] for PowerPC 970-based computers were manufactured by IBM:

*CPC925{{snd}} Designed by Apple<ref>{{cite web|url=https://www.youtube.com/watch?v=iwsn27J_tlo  |archive-url=https://ghostarchive.org/varchive/youtube/20211221/iwsn27J_tlo |archive-date=December 21, 2021 |url-status=live|title=WWDC 2003 Keynote |via=YouTube |author=Steve Jobs, Apple |date= June 25, 2003|access-date=October 16, 2009}}{{cbignore}}</ref> and called the ''U3'' or the ''U3H'' (which supports [[Error-correcting code|ECC]] memory). It is capable of supporting up to two PowerPC 970s or PowerPC 970FXs and has two 550&nbsp;MHz unidirectional processor buses, a 400&nbsp;MHz [[DDR SDRAM|DDR]] memory controller, x8 [[Accelerated Graphics Port|AGP]] and a 400&nbsp;MHz 16-bit [[HyperTransport]] tunnel. It fabricated on a 130&nbsp;nm process. Additionally, there was an unreleased U3Lite northbridge in development for the PowerBook G5, which never made it to market.
*CPC945{{snd}} Designed by IBM and called ''U4'' by Apple, it is capable of supporting two PowerPC 970MPs and has two 625&nbsp;MHz unidirectional processor buses, two memory controllers that support up to 64&nbsp;GB of 533&nbsp;MHz DDR2 SDRAM with ECC capability and has a x16 [[PCI Express|PCIe]] lane and an 800&nbsp;MHz 16-bit HyperTransport tunnel. It is fabricated on a 90&nbsp;nm process.

A CPC965 northbridge was canceled. Slated for release in 2007, it was to be a uniprocessor-only northbridge. Its features were a 533&nbsp;MHz DDR2 controller that supported up to 8&nbsp;GB ECC memory, a 8x PCIe bus, integrated four-port [[Gigabit Ethernet]] with [[IPv4]] [[Transmission Control Protocol|TCP]]/[[User Datagram Protocol|UDP]] offloading, USB 2.0 ports, a [[Flash memory|Flash]]-interface. The northbridge contains an integrated [[PowerPC 400#PowerPC 405|PowerPC 405]] core to provide system management and configuration capabilities.<ref>LaPedus, Mark (March 10, 2006). [http://www.eetimes.com/news/semi/showArticle.jhtml?articleID=193101381 "IBM rolls low-power processors, IP cores"] {{Webarchive|url=https://web.archive.org/web/20070926220729/http://www.eetimes.com/news/semi/showArticle.jhtml?articleID=193101381 |date=September 26, 2007 }}. ''EE Times''.</ref>

==Buses==
IBM uses its proprietary [[IBM Elastic Interface|Elastic Interface]] (EI) bus in the modules.<!-- The following reference is unreachable; ‣Andreas•⚖ 14:59, 17 May 2009 (UTC) --><!--<ref>[http://www.ibm.com/developerworks/power/library/pa-nldec04-poweron/index.html Guillaume Peron, "IBM PowerPC 970FX power-on reset mechanism" 15 Dec 2005]</ref>-->

==See also==
*[[Supercomputer]]s using the PowerPC 970:
**[[System X (supercomputer)|System X]]
**Some previous models of supercomputers in the [[Spanish Supercomputing Network]] used PowerPC processors, such as [[Magerit]] version 1 and [[MareNostrum]] version 2.
* [[List of Macintosh models grouped by CPU type]]

==References==
{{Reflist}}

==Further reading==
* "IBM's PPC970 Becomes Apple's G5". (July 7, 2003). ''[[Microprocessor Report]]''.
* "IBM Takes the Lead". (February 9, 2004). ''[[Microprocessor Report]]''.
* "IBM's Double-Shot of PowerPC". (November 7, 2005). ''[[Microprocessor Report]]''.

==External links==
*[http://archive.arstechnica.com/cpu/02q2/ppc970/m-ppc970-1.html Ars Technica article, part I]
*[http://archive.arstechnica.com/cpu/03q1/ppc970/ppc970-0.html Ars Technica article, part II]
*[https://web.archive.org/web/20051201034957/http://www-306.ibm.com/chips/techlib/techlib.nsf/techdocs/AE818B5D1DBB02EC87256DDE00007821 IBM PowerPC 970FX RISC Microprocessor User's Manual]
*[http://www-106.ibm.com/developerworks/library/pa-microdesign/?ca=dgr-lnxw07UnderstandPower Understanding 64-bit PowerPC architecture]
*[https://web.archive.org/web/20070518150548/http://www.realworldtech.com/page.cfm?NewsID=353&date=02-15-2006#353 ISSCC 2006: IBM PowerPC 970MP]
*IBM Documentation: [https://web.archive.org/web/20090129183103/http://www-01.ibm.com/chips/techlib/techlib.nsf/products/PowerPC_9XX_Microprocessors PowerPC 9XX Microprocessors]

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[[Category:PowerPC microprocessors|970]]
[[Category:IBM microprocessors|970]]
[[Category:Power microprocessors]]
[[Category:64-bit microprocessors]]