Nehalem is built on the 45 nm process, is able to run at higher clock speeds without sacrificing efficiency, and is more energy-efficient than Penryn microprocessors. Hyper-threading is reintroduced, along with a reduction in L2 cache size, as well as an enlarged L3 cache that is shared among all cores. Nehalem is an architecture that differs radically from NetBurst, while retaining some of the latter's minor features.
Nehalem later received a die-shrink to 32 nm with Westmere, and was fully succeeded by "second-generation" Sandy Bridge in January 2011.
Technology
Microarchitecture of a processor core in the quad-core implementation
Cache line block on L2/L3 cache was reduced from 128 bytes in NetBurst & Merom/Penryn to 64 bytes per line in this generation (same size as Yonah and Pentium M).
Instruction Fetch Unit (IFU) containing second-level branch predictor with two level Branch Target Buffer (BTB) and Return Stack Buffer (RSB). Nehalem also supports all predictor types previously used in Intel's processors like Indirect Predictor and Loop Detector.[7]
sTLB (second level unified translation lookaside buffer) (i.e. both instructions and data) that contains 512 entries for small pages only, and is again 4 way associative.[8]
3 integer ALU, 2 vector ALU and 2 AGU per core.[9]
Native (all processor cores on a single die) quad- , hex-, and octa-core processors
On average, Nehalem provides a 15–20% clock-for-clock increase in performance per core.
Overclocking is possible with Bloomfield processors and the X58 chipset. Lynnfield processors use a PCH removing the need for a northbridge.[14]
Nehalem processors incorporate SSE4.2 SIMD instructions, adding seven new instructions to the SSE 4.1 set in the Core 2 series. The Nehalem architecture reduces atomic operation latency by 50% in an attempt to eliminate overhead on atomic operations such as the LOCK CMPXCHGcompare-and-swap instruction.[15]
Variants
Lynnfield processors feature 16 PCIe lanes, which can be used in 1x16 or 2x8 configuration.
1 6500 series scalable up to 2 sockets, 7500 series scalable up to 4/8 sockets.[17]
Server, workstation, and desktop processors
Intel states the Gainestown processors have six memory channels. Gainestown processors have dual QPI links and have a separate set of memory registers for each link in effect, a multiplexed six-channel system.[30][31]
^Gruener, Wolfgang (August 10, 2008), Nehalem = i7: Intel unveils new Core processor brand, TG Daily, archived from the original on August 14, 2009, retrieved August 11, 2008
^Intel Details Upcoming New Processor Generations, Intel Corporation, March 28, 2007
^Ian, King (October 20, 2008), Intel's new faster chip right on AMD's heels, The Seattle Times
^Jones, George (February 9, 2008), IAMD vs Intel: The future of desktop CPUs, PC Advisor UK
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^Kanter, David. "Inside Nehalem: Intel's Future Processor and System".
^Kanter, David. "Inside Nehalem: Intel's Future Processor and System".
^Johan De Gelas. "AnandTech - High-End x86: The Nehalem EX Xeon 7500 and Dell R810". Retrieved December 29, 2014.
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^Intel Xeon Processor 5500 Series Product brief, (Document Number: 321579-001US) (PDF), Intel, April 1, 2009, retrieved August 27, 2010
^Core i7 to make leap to Xeon in early 2009, Legacy.macnn.com, archived from the original on December 7, 2008, retrieved November 24, 2008
^Fuad Abazovic (January 28, 2009), Nehalem based Xeon comes Mar 29th, Fudzilla.com, retrieved January 28, 2009[permanent dead link]
^Intel Xeon Processor 3500 Series, Intel, April 1, 2009, retrieved April 10, 2009
^ a b c dTeglet, Traian (November 13, 2008), Intel to Add New Nehalem Xeon Processor, softpedia, retrieved November 13, 2008
^"Intel Core i7 Processor Extreme Datasheet, Volume 2, (Document Number: 320835-002)" (PDF). Intel. November 1, 2008. Retrieved March 24, 2009.
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^Intel to launch new Core i7 960 and Celerons
^Intel Core i5-750, AnandTech, June 17, 2009
^Intel Quietly Announces Core i5, Xtreview, June 26, 2009
^Intel Xeon Processor 5500 Series Datasheet Volume 2 (PDF), Intel, March 2009, retrieved May 1, 2009
Further reading
InfoWorld review: Intel's Westmere struts its stuff, InfoWorld, March 16, 2010
IDF: Intel Clarkdale Up Close and Personal, X-bit Labs, September 24, 2009, archived from the original on March 8, 2011
Intel Core i7 Processors: Nehalem and X58 Have Arrived, Hot Hardware, November 3, 2008, archived from the original on March 6, 2009, retrieved June 10, 2009
Intel Core i7 CPU & Nehalem Architecture Review, hardCOREware.net, November 3, 2008, archived from the original on November 6, 2008
Intel Nehalem Core i7 Series Complete Review, PC Perspective, November 3, 2008, archived from the original on November 6, 2008, retrieved November 3, 2008
Intel Nehalem Core i7 940 Review, Xtreview, October 1, 2008
Altavilla, Dave (March 17, 2008), Intel Showcases Dunnington, Nehalem and Larrabee Processors, HotHardware, archived from the original on May 23, 2012, retrieved March 26, 2008
Shrout, Ryan (March 28, 2008), Intel Slides and Nehalem architecture information, PC Perspective, archived from the original on May 14, 2010, retrieved April 23, 2007
Stokes, Jon (March 28, 2007), Intel drops a Nehalem bomb on AMD's Fusion: integrated graphics, on-die memory controller, SMT, Ars Technica
