Intel Core i7

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Core i7
Central processing unit
Intel QuickPath Interconnect

Produced	From 2008
Common manufacturer(s)	Intel
Max CPU clock	2.66 GHz to 3.33 GHz
QuickPath Interconnect speeds	4.8 GT/s to 6.4 GT/s
Min feature size	45 nm
Instruction set	x86, x86-64, MMX, SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2
Microarchitecture	Nehalem
Cores	4 (physical), 8 (logical)
Socket(s)	Socket B (LGA 1366)
Core name(s)	Bloomfield

Intel Core i7 is a family of several Intel desktop x86-64 processors, the first processors released using the Intel Nehalem microarchitecture and the successor to the Intel Core 2 family. All three current models and two upcoming models are quad-core processors.^[1][2][3][4] The Core i7 identifier applies to the initial family of processors^[5][6] codenamed Bloomfield.^[7] Intel representatives state that the moniker Core i7 is meant to help consumers decide which processor to purchase as the newer Nehalem-based products are released in the future^[8]. The name continues the use of the Core brand.^[9] Core i7, first assembled in Costa Rica,^[10] was officially launched on November 17, 2008^[11] and is manufactured in Arizona, New Mexico and Oregon, though the Oregon plant is moving to the next generation 32 nm process.

Contents 1 Features 2 Processor cores 2.1 Performance 2.2 Overclocking 2.3 Drawbacks 2.4 Discontinuation 2.5 Mobile implementations 3 See also 4 References 5 External links

[edit] Features

The Nehalem microarchitecture has many new features, some of which are present in the Core i7. The ones that represent significant changes from the Core 2 include:

• The new LGA 1366 socket is incompatible with earlier processors.
• On-die memory controller: the memory is directly connected to the processor. It is called the uncore part and runs at a different clock (uncore clock) of execution cores.
  • Three channel memory: each channel can support one or two DDR3 DIMMs. Motherboards for Core i7 generally have three, four (3+1), six, or nine DIMM slots.
  • Support for DDR3 only.
  • No ECC support.
• The front side bus has been replaced by the Intel QuickPath Interconnect interface. Motherboards must use a chipset that supports QuickPath.
• The following caches:
  • 32 KB L1 instruction and 32 KB L1 data cache per core
  • 256 KB L2 cache (combined instruction and data) per core
  • 8 MB L3 (combined instruction and data) "inclusive", shared by all cores
• Single-die device: all four cores, the memory controller, and all cache are on a single die.
• "Turbo Boost" technology allows all active cores to intelligently clock themselves up in steps of 133 MHz over the design clock rate as long as the CPU's predetermined thermal and electrical requirements are still met.^[12]
• Re-implemented Hyper-threading. Each of the four cores can process up to two threads simultaneously, so the processor appears to the OS as eight CPUs. This feature was present in the older NetBurst microarchitecture but was never introduced into Core since Core was a descendant of the Pentium III family.
• Only one QuickPath interface: not intended for multi-processor motherboards.
• 45nm process technology.
• 731M transistors.
• 263 mm² die size.
• Sophisticated power management can place an unused core in a zero-power mode.
• Support for SSE4.2 & SSE4.1 instruction sets.

Intel Core i7 processor family
Logo	New Logo	Desktop
		Code-named	Core	Date released
		Bloomfield	quad (45 nm)	Nov 2008
		Bloomfield Extreme Edition	quad (45 nm)	Nov 2008
List of Intel Core i7 microprocessors

[edit] Processor cores

• The clock rates listed here are as specified by Intel for normal mode. "Turbo boost" can increase the rate on active cores in steps of the base clock (133 MHz if not overclocked) up to a predetermined limit for short periods when required, which can be useful with single threaded applications.
• The I7-965 XE and I7-975 XE have separate unlocked multipliers for memory and cores.
  • Core clock above those in the table are not guaranteed by Intel.^[4] Rates above 5 GHz have been reported.^{[citation needed]}
  • Memory rates above those in the table are not guaranteed by Intel.^[4] Rates above DDR3-2000 have been reported.^{[citation needed]}
• The processor has a Thermal Design Power of 130 W and will slow itself down if this power is exceeded. This feature can be disabled from an option in most of the new motherboards' BIOS.^[13]
• Prices are Intel's wholesale prices for lots of 1,000 units in USD at product launch.

Core i7 Model[14]	nm	Cores (Threads)	Clocks (GHz)			Multipliers (x Base)		Price (USD)	Cache	Memory controller[2][3][4]	QuickPath Interface	Thermal Design Power [13]	Socket	Release date
			Core	Uncore	Base	Core	Uncore
i7-920	45nm	4 (8)	2.66	2.13	.133	20	16	273	256 KB L2/core 8 MB shared L3	3x DDR3-800/1066	1x 4.8 GT/s	130 W	LGA 1366	2008-11-17
i7-940			2.93			22		538
i7-950[15]			3.06			23		562						2009-06-03
i7-965 Extreme Edition			3.20	2.66		24	20	985			1x 6.4 GT/s			2008-11-17
i7-975 Extreme Edition [15][16]			3.33			25		999						2009-06-03

[edit] Performance

• The Inquirer managed to get a 965 engineering sample to a core clock rate of up to 4GHz with fan cooling and Turbo Booster, this is quite impressive but may not be reachable on all home systems.
• IT OC Taiwan overclocked an engineering sample of the 965, to 4.20 GHz with a QPI rate of 200 MHz and a multiplier value of 21.0x. A vCore setting of 1.72V was used, which is far higher than the stock voltage of 1.25V and could lead to damage to the cpu or motherboard.^[17]
• A Core i7 940 system running at stock clock rates has obtained a 3DMark Vantage benchmark CPU score of 17,966.^[18] A Core i7 920 system scored 16,294 running at stock clock rates. An Intel Core 2 Extreme QX9770, a very expensive member of the previous generation of Intel processors (costing over four times the price of the 920 at its launch), scored 13,182 also running at stock clock rates.^[19]

• AnandTech tested the Intel QuickPath Interconnect (4.8 GT/s version) and found the copy bandwidth using triple-channel 1066 MHz DDR3 was 12.0 GB/s. A 3.0 GHz Core 2 Quad system using dual-channel 1066 MHz DDR3 achieved 6.9 GB/s.^[20]

• Maximum PC has discovered that Intel has unlocked the clock and memory multipliers on retail 920s and 940s. This is allegedly due to consumer feedback.^[21]

• Core i7-975 will have the new D0 Stepping. Tests made by X-bit labs shows that it has better energy efficiency and overclockability than C0 stepping.^[22]

[edit] Overclocking

The process of overclocking the Core i7 architecture is similar to that of the AMD architecture due to the on-die MCH.^[23] Over-clocking will be possible with the 900 series and a motherboard equipped with the X58 chipset. In early October 2008, reports surfaced that it will not be possible to use "performance" DDR3 DIMMs that require voltages higher than 1.65v, because the integrated memory controller within the Core i7 will be damaged.^[24]

The Core i7 has three memory channels, and the channel bandwidth can be selected by setting the memory multiplier. However, in early benchmarks, when the clock rate is set higher than a threshold (1333 for the 965XE) the processor will only access two memory channels simultaneously. A 965XE has higher memory throughput with 3xDDR3-1333 than with 3xDDR3-1600, and 2xDDR3-1600 has almost identical throughput to 3xDDR3-1600.

[edit] Drawbacks

The Core i7 does not support error-correcting memory.^[2][3][4]. Some motherboards with an LGA 1366 socket support both Core i7 and the Xeon 35xx and 55xx series processors, and advertise support for ECC memory.^{[25] [26]} However ECC functionality is only available if a Xeon is installed, not if a Core i7 is installed.

Some early articles^[specify] suggested that i7's design is not ideal for gaming performance. In a test performed on leaked hardware, a Core i7 940 compared to a QX9770 showed the Core i7 to be slower than Yorkfield clock cycle-for-clock cycle in two trials, while being faster in two others. The difference in all cases was small, and was due to the significantly smaller sized L2 cache on the processor cores, with each core able to access its own 256 kB of L2 cache. In contrast, the most recent Yorkfields have up to 12 MB of L2 cache. To help compensate, the Core i7 also has a new L3 cache of 8 MB, shared among all four cores, similar to AMD's "Barcelona" processors. This is due to the trend of games making use of more threads, and with hyper-threading the Core i7 can scale more than 4x faster, such as in Cinebench tests.^[27] However, more recent testing done on all clock rates of official hardware with final drivers and BIOS revisions show that Core i7 at the very least beats Yorkfield clock cycle-for-clock cycle, and in most cases exceeds it by an average of about 17%.^[28] But when it comes to high-end multi-GPU environments (NVIDIA 3-way SLI and ATI Crossfire X), the i7 is revealed to be much faster than Yorkfield (QX9770) in clock cycle-for-clock cycle.^[29]

[edit] Discontinuation

With the launch of 32 nm processors in the upcoming months, Intel will discontinue some Atom, Celeron, Pentium, Core 2, and even Core i7 models. The Core i7 940 is scheduled to be discontinued in Q3, 2009^[30]. Unlike Intel's other existing processor lines, the Core i7 will continue to be manufactured and used while the other lines will be phased out after the launch of the Core i5 and Core i3 processors.

[edit] Mobile implementations

While the Core i7 is a desktop processor, the first attempt at using it to power a gaming laptop was made by Sager, a laptop manufacturer that uses the Core i7 in its np9280 gaming laptop. ^[31]

[edit] See also

• List of Intel Core i7 microprocessors
• Phenom II, competitor product from AMD

[edit] References

[edit] External links

Wikimedia Commons has media related to: Intel Core i7

• Intel Core i7 web page
• Intel Core i7 Extreme Edition web page
• Intel Core i7 Processors: Nehalem and X58 Have Arrived - HotHardware Performance Evaluation
• Intel Core i7-975 XE and Core i7-950 Review: Lineup Update and New Stepping

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