The Real Story about IBM's POWER6

April 2008:  IBM’s POWER6 marketing is certainly full of espirit de “core”, focusing on IBM’s processor technology.  Marketing aside, a migration to the new IBM processor technology may contain pitfalls that customers should be aware, and wary of.

Fact 1:  The instruction execution approach has changed going from POWER4/5 to POWER6.  With POWER6 IBM has dropped the out-of-order execution used by POWER4/5 to a mostly in-order approach.

Fact 2:  IBM’s commercial performance metric for POWER (System p) servers (rPerf ) show that IBM’s POWER6 has not delivered anywhere near two-times (2X) performance per core even though the frequency has more than doubled. (2)

Fact 3:  The max rated system electrical load  for the POWER6-595 server has increased nearly 5000 watts over the POWER5-p595 for the same number of processors.(4)

Fact 4: IBM has raised the per core cost of IBM software 20% for POWER6 as compared to POWER5.(8)

Fact 5:  A migration to a new version of AIX, AIX 6.1, will be needed In order to get an operating system that is designed to more fully exploit POWER6.(9) 

Fact 6:  POWER6 servers still do not support hard partitions with full electrical isolation.

Fact 7:  An industry analyst recently wrote that they believe that IBM may exit the semiconductor business in the future due to high fab costs, competition and changing business models.(11)

¹ Presentation:  “Maximizing Application Performance on POWER” IBM Linux on POWER GCC Team Lead, April 19, 2007, page 8, http://www.power.org/swsummit/download/SW_Summit_gcc_and_tool_chain_Peter.pdf 

² When IBM announced the POWER6 processor they wrote, ""At 4.7 GHz, the dual-core POWER6™ processor doubles the speed of the previous generation POWER5™ while using nearly the same amount of electricity to run and cool it. This means customers can use the new processor to either increase their performance by 100 percent or cut their power consumption virtually in half." See IBM Press Release: http://www-03.ibm.com/press/us/en/pressrelease/21580.wss, however the rperf show much less than 100% gain as referenced by: http://www-03.ibm.com/systems/p/hardware/rperf.html

³  IBM Systems Performance Report:  http://www-03.ibm.com/systems/p/hardware/reports/system_perf.html

⁴ http://www-01.ibm.com/common/ssi/index.wss?DocURL=http://www-01.ibm.com/common/ssi/rep_ca/7/897/ENUS108-257/index.html&InfoType=AN&InfoSubType=CA&InfoDesc=Announcement+Letters&panelurl=index.wss%3F&paneltext=Announcement%20letter%20search,  POWER 595 (POWER6) 27,500 watts max for 64 cores, p595 (POWER5) 22,710 watts max for 64 cores. Difference 4790 watts

⁵ “… POWER6* processor, offers significantly higher clock frequencies and uses improved lithography with smaller device sizes than its predecessors.
As processor power and heat increase and components are packed ever more tightly, they increase not only in performance but also in their power consumption and heat generation, compounding what was already a thermal challenge.
As a result, traditional high-margin designs can no longer take full advantage of the technology advances provided by POWER6 processor-based systems.”
Source:  IBM Journal of Research and Development: EnergyScale for IBM POWER6 microprocessor-based systems, http://www.research.ibm.com/journal/rd/516/mccreary.html

⁶ HP rx2600, 1.66GHz 18M Itanium2, 1chip/2cores/2 core per chip
(See the disclosure, Although two cores were enabled during testing,the SPEC CPU2006 benchmarks used only one core) 15.7 SPECint_base2006.  Results as of 4/14/08 see: www.spec.org

 IBM p 570, 4.7 GHz POWER6, 1chip/1cores/2 core per chip
17.8 SPECint_base2006.  Results as of 4/14/08 see: www.spec.org

⁷ HP rx2600, 1.66GHz 18M Itanium2, 1chip/2cores/2 core per chip
(See the disclosure, Although two cores were enabled during testing,the SPEC CPU2006 benchmarks used only one core) 19.9 SPECfp_base2006.  Results as of 4/14/08  see: www.spec.org

 IBM p 570, 4.7 GHz POWER6, 1chip/1cores/2 core per chip
18.7 SPECfp_base2006.  Results as of  4/14/08 see: www.spec.org

⁸ https://www-112.ibm.com/software/howtobuy/passportadvantage/valueunitcalculator/vucalc.wss

⁹ http://www-03.ibm.com/servers/aix/6/preview.html, “Like the predecessor releases of the AIX OS, Version 6.1 fully exploits the newest POWER™ processors, the IBM POWER6™ processor”

¹⁰ http://www.hp.com/products1/servers/scalableservers/superdome/mixing.html?jumpid=reg_R1002_USEN

¹¹ In-Stat Press ReleaseFebruary 27, 2008 “Intel Strategy Draws New Competitors”
http://www.in-stat.com/press.asp?ID=2249&sku=IN0804280SI, “ “IBM will continue pushing the POWER processor architecture for servers and consumer electronics, but In-Stat believes it may exit the semiconductor business within a decade due to high fab costs, competition, and changing business models.”

¹² http://www.ibm.com/investor/1q08/presentation/1q08prepared.pdf

¹³ http://www.eetimes.com/news/semi/showArticle.jhtml?articleID=207201003
 “Soitec explained that the downward trend in sales in the fourth quarter stems from "the continuing weak demand and the absence of a favorable impact from the launch of new products by major customers.  “Actual demand from the company's two main customers, namely Advanced Micro Devices, Inc. and IBM Corp., that is covered by the contractual minimum quantities is indeed running behind schedule by around 14 percent.“