Intel Core i7
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 | |
| Produced | From 2008 |
|---|---|
| Common manufacturer(s) | Intel |
| Max CPU clock | 2.66 GHz to 3.33 GHz |
| QuickPath Interconnectspeeds | 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 three 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 i7identifier 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 buy when new Nehalem-based products release down the road[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[hide] |
[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.
- The front side bus has been replaced by the Intel QuickPath Interconnect interface.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 dropped in Core.
- 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 XE | 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 (133MHz 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 has separate unlocked multipliers for memory and cores.
- Core clock above those in the table are not guaranteed by Intel.[4] Rates above 5GHz 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 130W 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 | Cache | Memory controller[2][3][4] | QuickPath Interface | TDP [13] | Socket | Release date | |||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Core | Uncore | Base | Core | Uncore | ||||||||||
| I7-920 | 45nm | 4 (8) | 2.66 | 2.13 | .133 | 20 | 16 | $284 | 256 KB L2/core 8 MB shared L3 | 3x DDR3-800/1066 | 1x 4.8 GT/s | 130W | LGA 1366 | 2008-11-17 |
| I7-940 | 2.93 | 22 | $562 | |||||||||||
| I7-950[15] | 3.06 | ? | 23 | ? | 2009-5-31 | |||||||||
| I7-965 Extreme Edition | 3.20 | 2.66 | 24 | 20 | $999 | 1x 6.4 GT/s | 2008-11-17 | |||||||
| I7-975 Extreme Edition [15][16] | 3.33 | ? | 25 | ? | 2009-5-31 | |||||||||
[edit]Performance
- The Inquirer managed to get a 965 engineering sample to a core clock speed of up to 4GHz with fan cooling and Turbo Booster alone.[17]
- IT OC Taiwan overclocked an engineering sample of the 965, to 4.20 GHz with a QPI speed 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 of 1.25V.[18]
- A Core i7 940 system running at stock speeds has obtained a 3DMark Vantage benchmark CPU score of 17,966.[19] A Core i7 920 system scored 16,294 running at stock speeds. An IntelCore 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 speeds.[20]
- 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.[21]
- Maximum PC has discovered that Intel has unlocked the clock and memory multipliers on retail 920's and 940's. This is allegedly due to consumer feedback. [22]
- Core i7-975 will have the new D0 Stepping.
[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.[17]
[edit]Drawbacks
The Core i7 does not support error-correcting memory.[2][3][4] Some high-end motherboards that support the Core i7 advertise support for ECC memory, for example Supermicro's C7X58 and X8SAX (see Supermicro's X8SAX page), however, in the same motherboard manuals, it is made clear that ECC is only supported if the CPU has the feature enabled.
Some early articles 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-for-clock 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 (HT) the Core i7 can scale more than 4x faster, such as in cinebench tests.[25] 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-for-clock, and in most cases exceeds it by an average of about 17%.[26] 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-for-clock.[27]
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