Nehalem (microarchitecture)

For other uses, see Nehalem (disambiguation).

Nehalem /nəˈheɪləm/^[1] is the codename for Intel's 45 nm microarchitecture released in November 2008.^[2] It was used in the first generation of the Intel Core i5 and i7 processors, and succeeds the older Core microarchitecture used on Core 2 processors.^[3] The term "Nehalem" comes from the Nehalem River.^[4][5]

Nehalem

Logo for Core i7 Bloomfield processors
General information
Launched	November 11, 2008; 16 years ago (November 11, 2008)
Marketed by	Intel
Designed by	Intel
Common manufacturer	Intel
Performance
Max. CPU clock rate	1.06 GHz to 3.33 GHz
QPI speeds	4.80 GT/s to 6.40 GT/s
DMI speeds	2 GT/s
Cache
L1 cache	64 KB per core (32 KB data + 32 KB instructions)
L2 cache	256 KB per core
L3 cache	2 MB to 24 MB shared
Architecture and classification
Technology node	45 nm
Microarchitecture	Nehalem
Instruction set	x86-16, IA-32, x86-64
Instructions	MMX, SSE, SSE2, SSE3, SSSE3, SSE4, SSE4.1, SSE4.2
Extensions	VT-x, VT-d
Physical specifications
Transistors	731M to 2300M 45 nm
Cores	1-6 (1-8 Xeon)
Sockets	LGA 1156 LGA 1366 LGA 1567 μPGA 988
Products, models, variants
Core names	Clarksfield Lynnfield Bloomfield Jasper Forest Gainestown (Nehalem-EP) Beckton (Nehalem-EX) Aubrurndale Havendale
Product code name	NHM
Models	Core i5-7xx Core i7-8xx Core i7-9xx Extreme Xeon 3000/5000/7000 Mobile Core i7-7xxQM Mobile Core i7-8xxQM Mobile Core i7-9xxXM Extreme
History
Predecessors	Core (tock) Penryn (tick)
Successors	Westmere (tick) Sandy Bridge (tock)
Support status
Unsupported

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).
• Hyper-threading reintroduced.
• Intel Turbo Boost 1.0.^[6]
• 2–24 MiB L3 cache with Smart Cache in some models.
• 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
• Intel QuickPath Interconnect in HEDT, server, and workstation models and Direct Media Interface on other models replacing the legacy front side bus.
• 64 KB L1 cache per core (32 KB L1 data and 32 KB L1 instruction), and 256 KB L2 cache per core.
• Integration of PCI Express and DMI into the processor in mid-range models, replacing the northbridge.
• Integrated memory controller supporting two or three memory channels of DDR3 SDRAM or four FB-DIMM2 channels.
• Second-generation Intel Virtualization Technology, which introduced Extended Page Table support, virtual processor identifiers (VPIDs), and non-maskable interrupt-window exiting. ^[10]
• SSE4.2 and POPCNT instructions.
• Macro-op fusion now works in 64-bit mode.
• 20 to 24 pipeline stages.^[11]

Translation lookaside buffer sizes^[12]

Cache		Page Size
Name	Level	4 KB	2 MB
DTLB	1st	64	32
ITLB	1st	128	7 / logical core
STLB	2nd	512	none

Performance and power improvements

It has been reported that Nehalem has a focus on performance, thus the increased core size.^[13] Compared to Penryn, Nehalem has:

• 10–25% better single-threaded performance / 20–100% better multithreaded performance at the same power level
• 30% lower power consumption for the same performance
• 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 CMPXCHG compare-and-swap instruction.^[15]

Variants

Processing Cores (interface)	Process	Die Size	million transistors	CPUID	Model	Stepping	Mobile	Desktop, UP Server	DP Server	MP Server
Eight-Core (Quad-Channel)	45 nm	684 mm2	2.300[16]	206E6	46	D0				Beckton (80604)
Quad-Core (Triple-Channel)		263 mm2	731	106A4 106A5	26	C0/C1 D0		Bloomfield (80601)	Gainestown (80602)
Quad-Core (Dual-Channel, PCIe)		296 mm2	774	106E4 106E5	30	B0 B1	Clarksfield (80607)	Lynnfield (80605)	Jasper Forest (80612)
Dual-Core (Dual-Channel, PCIe, Graphics Core)			?				Auburndale (80608) (canceled)	Havendale (80606) (canceled)

• 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

Main articles: List of Intel Core processors and List of Intel Xeon processors (Nehalem-based)

Codename	Market	Cores (threads)	Socket	Processor Branding & Model		CPU Clock rate	Turbo	TDP	Interfaces		L3 cache	Release Date	Price
									Chipset	Memory
Beckton1	MP Server / DP Server	8 (16)	LGA 1567	Xeon 7000[18]	X7560	2.26 GHz	Yes	130 W	4× QPI 6.4 GT/s	DDR3-800 / 1066 (Up to 4x with SMB-Ready motherboard)	24 MB	2010-03-30[19]	$3692
					X7550	2.0 GHz					18 MB		$2837
					X6550								$2461
					L7555	1.86 GHz		95 W	4× QPI 5.86 GT/s		24 MB		$3157
		6 (12)			E7540	2.0 GHz		105 W	4× QPI 6.4 GT/s		18 MB		$1980
					E6540						12 MB		$1712
					E7530	1.86 GHz			4× QPI 5.86 GT/s				$1391
					L7545			95 W			18 MB		$2087
		6 (6)			X7542	2.66 GHz		130 W					$1980
		4 (8)			E7520	1.86 GHz	No	105 W	4× QPI 4.8 GT/s				$856
					E6510	1.73 GHz					12 MB		$744
Gainestown	DP Server[20]	4 (8)	LGA 1366	Xeon 5000[21]	W5590	3.33 GHz	Yes	130 W	2× QPI 6.4 GT/s	3× DDR3-13331	8 MB	2009-08-09	$1600
					W5580	3.2 GHz						2009-03-29[22]	$1500
					X5570	2.93 GHz		95 W					$1286
					X5560	2.8 GHz							$1072
					X5550	2.66 GHz							$858
					E5540	2.53 GHz		80 W	2× 5.86 GT/s	3× DDR3-10661			$744
					E5530	2.4 GHz							$530
					E5520	2.26 GHz							$373
					L5530	2.4 GHz		60 W				2009-08-09	$744
					L5520	2.26 GHz						2009-03-30	$530
					L5518	2.13 GHz							$
		4 (4)			E5507	2.26 GHz	No	80 W	2× 4.8 GT/s	3× DDR3-8001	4 MB	2010-03-16	$266
					E5506	2.13 GHz						2009-03-29
					L5506	2.13 GHz		60 W					$423
					E5504	2.0 GHz		80 W					$224
		2 (4)			L5508	2.0 GHz	Yes	38 W	2× 5.86 GT/s	3× DDR3-1066	8 MB		$
		2 (2)			E5503	2.0 GHz	No	80 W	2× 4.8 GT/s	3× DDR3-800	4 MB	2010-03-16	$224
					E5502	1.86 GHz						2009-03-29	$188
Jasper Forest		4 (8)			EC5549	2.53 GHz	Yes	85 W	1× 5.86 GT/s	3× DDR3-1333	8 MB	2010-02-11	$530
					LC5528	2.13 GHz		60 W	1× 4.8 GT/s	3× DDR3-1066			$519
					LC5518	1.73 GHz		48 W
		4 (4)			EC5509	2 GHz	No	85 W					$265
		2 (4)			EC5539	2.27 GHz		65 W	1× 5.86 GT/s	3× DDR3-1333	4 MB		$387
Bloomfield	UP Server[23]	4 (8)		Xeon 3000[24]	W3580	3.33 GHz	Yes	130 W	1× QPI 6.4 GT/s	3× DDR3-1333	8 MB	2009-08-09	$999
					W3570	3.2 GHz						2009-03-29[24]
					W3565	3.2 GHz			1× QPI 4.8 GT/s	3× DDR3-1066		2009-11-01	$562
					W3550	3.06 GHz						2009-08-09
					W3540	2.93 GHz						2009-03-29[24]
					W3530	2.8 GHz						2010-03-16	$294
					W3520	2.66 GHz						2009-03-29[24]	$284
		2 (2)			W3505	2.53 GHz	No				4 MB		$
					W3503	2.4 GHz							$
Jasper Forest		4 (4)			EC3539	2.13 GHz		65 W	DMI		8 MB	2010-02-11	$302
		2 (4)			LC3528	1.73 GHz	Yes	35 W		3× DDR3-800	4 MB
		1 (1)			LC3518		No	23 W			2 MB		$192
Lynnfield		4 (8)	LGA 1156		X3480	3.06 GHz	Yes	95 W	DMI	2× DDR3-1333	8 MB	2010-05-30	$612
					X3470	2.93 GHz						2009-09-08	$589
					X3460	2.8 GHz							$316
					X3450	2.66 GHz							$241
					X3440	2.53 GHz							$215
					L3426	1.86 GHz		45 W					$284
		4 (4)			X3430	2.4 GHz		95 W					$189
Bloomfield	Enthusiast Desktop[25]	4 (8)	LGA 1366	Core i7 Extreme	975X[26]	3.33 GHz	Yes	130 W	1× QPI 6.4 GT/s	3× DDR3-1066		2009-05-31	$999
					965X	3.2 GHz						2008-11-17
				Core i7	960[27]	3.2 GHz			1× QPI 4.8 GT/s			2009-10-20	$562
					950[26]	3.06 GHz						2009-05-31
					940	2.93 GHz						2008-11-17
					930	2.8 GHz						2010-02-28	$294
					920	2.66 GHz						2008-11-17	$284
Lynnfield	Performance Desktop		LGA 1156		880	3.06 GHz	Yes	95 W	DMI	2× DDR3-1333		2010-05-30	$583
					875K	2.93 GHz							$342
					870[28]							2009-09-08	$562
					870S	2.66 GHz		82 W				2010-07-19	$351
					860	2.8 GHz		95 W				2009-09-08	$284
					860S	2.53 GHz		82 W				2010-01-07	$337
		4 (4)		Core i5	760	2.8 GHz		95 W				2010-07-17	$209
					750[28]	2.66 GHz		95 W				2009-09-08	$196
					750S	2.4 GHz		82 W				2010-01-07	$259
Jasper Forest	Embedded Desktop	1 (2)	LGA 1366	Celeron	P1053	1.33 GHz	No	30 W		3× DDR3-800	2 MB	2010-12-02	$160

• 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.^[29][30]

Mobile processors

Main article: List of Intel Core i7 processors

Codename	Market	Cores / Threads	Socket	Processor Branding & Model		Core Clock rate	Turbo	TDP	L3 cache	Interface	Release Date	Price
Clarksfield	Extreme mobile	4 (8)	Socket G1 rPGA 988	Core i7 Extreme	940XM	2.13 GHz	Yes	55 W	8 MB	* DMI * 2x DDR3-1333 * PCIe 1 x16 / 2 x8	2010-06-21	$1096
					920XM	2.0 GHz					2009-09-23	$1054
	Quad-core mobile Performande mobile			Core i7	840QM	1.86 GHz		45 W			2010-06-21	$568
					820QM	1.73 GHz					2009-09-23	$546
					740QM				6 MB		2010-06-21	$378
					720QM	1.6 GHz					2009-09-23	$364

See also

• List of Intel CPU microarchitectures
• Tick–tock model