Posted:2008-11-05 By processor review Number of View:362837
INTEL CORE I7 920 REVIEW
BENCHMARK AND OVERCLOCKING
By :processor review
Posted:2008-11-05
xtreview is your : Video card - cpu - memory - Hard drive - power supply unit source
The announced in 2006, core architecture , marked the beginning of new high performance desktop and mobile systems. Processors on base Of core combined the superiority on performance over NetBurst architecture , low energy consumption ( low heat emission ) and overclocking potential. The architecture core helped Intel company to avoid the economic problems, connected with relative unpopularity of NetBurst processors . During the last two years Intel consecutively enlarged the possibilities of core architecture , released new revisions, and recently transferred the release of processors to the 45nm technical process. In 2007 Intel stated about the announcement of nehalem architecture ( processors core i7), built on base Of core with a number of cardinal update :
The memory controller was transferred from the north bridge (motherboard) directly in the processor itself
support 3- X (triple) channel operation mode
in contrast to Kentsfield/yorkfield, which consist on two crystals with 2 core each, all 4 core Bloomfield are located on one crystal
At the given moment, the presented core i7 consists on three 4- core processors: 920, 940 and 965 Extreme edition.
Core i7 965 Extreme edition
Core i7 940
Core i7 920
Socket
LGA 1366
Technical process
45 nm
Quantity of core/threads
4/8
Frequency
3.20 GHz
2.93 GHz
2.66 GHz
Multiplier
x 24.0
x 22.0
x 20.0
QPI
1 x 6.4 GT/s
1 x 4.8 GT/s
1 x 4.8 GT/s
Cache
4 x 256 KB L2/8Mb L3
Supported memory type
DDR 3-800/1066/ 1333/1600
DDR 3-800/1066
DDR 3-800/1066
TDP, in watt
130
Price in parties from 1000 pieces
$999
$562
$284
And here finally we have some pre-series models processors core i7.
Thus, before us the elder and the low-end Core i7 representatives , Core i7 965 Extreme and core i7 920.
The new processor Core i7 is different from Intel core .
The integration of memory controller in the processor core, increased the crystal size , grew in the number of pins , in consequence the CPU surface increased from 38x38 to 42x45 mm.
Core I7 920 Cooler :
Since Core i7 920 is more interesting for most user due to its price (let us recall it will cost $284(wholesale) vs 562$ and 999$ ) we decided to focus mainly on this processor .
Here is the default cooler for this model (Core i7 920).
The new cooler has a larger size and bigger fan in comparison with LGA 775 .
Note the cooling of 775 processor will not be compatible with 1366 socket .
Core I7 920 in details :
But here thermalright company already propose for its most popular cooler a fasting in order to use the old cooler with 1366 socket . The model thermalright ultra-120 eXtreme will be used in out test .
After installing this processor on the motherboard Intel DX58SO on base of x58 chipset , CPU-z will reflect the following information:
Our processor is based on the early stepping C0. Series models will have a newer stepping and correspondingly, possess lower VID (standard voltage), and also, they can be characterized by higher overclocking potential…
Core I7 920 operating temperature :
According to the utility CoreTemp version 0.99, the processor temperature with the regular box Intel cooler , varies in the region 35-40 degrees . Under load (using OCCT utility version 2.0.0 ) the temperature rose to 55-60 degrees .
Core I7 920 overclocking :
The default voltage for this processor is 1.2V (1.16 with full load) , in this case the processor was stable at the frequency 3000 MHz (@ default voltage), but @3100Mhz it immediately crashed under OCCT test. After raising the core voltage to 1.3V it was possible to pass OCCT test at the frequency 3200 MHz . In this case 1.4V gave a stable 3400Mhz. The tendency is clear. We decided to give this processor 1.5V ( :-) , note it is not recommended to use 1.5v ), but @ 3600 MHz the system could not even POST. As it was explained later, the reason for the observed limitation is due to the QPI bus , in other words, The max stable QPI bus is 175 MHz (motherboard limitation ); therefore the processor overclock was limited to 3500MHz.
This result is modest taking in account the 45nm (4 GHz and above is typical ) and the relatively high voltage ( vcore ) simply does not impress.
Now let us say a few words about the memory : The memory frequency as before relay on (multiplier and QPI frequency) ; however, in our case only two multiplier are available : x3 and x4 , correspondingly to the maximum memory frequency 700Mhz , which is very small for DDR3. Therefore, memory timing were lowered to the smallest possible, 6-5-5-15. In this case the memory voltage was 1.74V (Note Intel recommend to not go over 1.65 v for the memory).
Core I7 920 vs Core architecture :
For comparison we used some popular four core processor : Intel Q6600 and Q9450, based on 65nm and 45nm technical processes.
First we decided to answer the question about the real advantages from the three(triple)-channel regime vs two(dual)-channel.
In practice there is no noticeable difference between dual and triple-channel memory operation modes . In the majority of tests the advantage or loss is reduced to a error of measurement, AND the advantage was seen only in some rare case . Later we will check if this advantage is so small due to the sufficiently low processor frequency .
Core i7 920 processor performance at default speed :
Let us examine the processor performance at default speed
Due to HT technology (Hyper-Threading) the advantage Of core i7 920 in multi-threaded tests reaches almost 100%, which greatly impresses.
Core i7 920 processor overclocked performance :
Since our Q6600 refused to overclock over 3.2 GHz we used in this test the Q9450 overclocked to 3.6 GHz and The i920 at 3.5 GHz .
It is clear that Core i7 920 could hold its advantage over Q9450 almost in all tests.
The average performance increase composed 30% which is already good.
Core i7 965 Extreme edition overclocking :
As we said above the overclock of our Core i7 920 was limited by the motherboard QIP bus , We decided to use in this case the extreme version which come with free multiplier. With air cooling, our copy overclocked to 3.8 GHz only , this is relatively modest for $1000 processors. At this frequency it was possible to pass SuperPi 32M, in 9 minutes 20 seconds.
Since our extreme processor proved to be a poor overclocker we decided to start another review with a new copy (to be published later) . But even with the low CPU overclock speed we set a records in the memory information exchange , which composed 21269MB/s and 21.1ns .
The maximum screen shot stable frequency was 4034MHz with 1.55V. Again the overclock of processor is a pure lottery, this is a matter of luck .
A few words a conclusion about Core i7 :
First, we give confirmation about the memory performance, that the difference between two and three- channel operation modes is low even at high CPU frequencies , and the memory latency is better (lower) in the dual-channel regime.
Core i7 does not love excessively high memory capacity . We can reach the frequencies 920-930Mhz with 6-6-5-15, but, absolutely all tests showed a performance loss relative to the same frequency with 7-7-7-16 or 8-7-6-18.
Now let us say a few words about the Intel memory voltage limit equal to : 1.65 v . In practice a constant use of memory with 2.2-2.3V have not influenced at all the overclocking potential/stability (Note we deal here with few days test , the time required to write this review , So some defect may appear for longer operation , but in our case 2.2-2.3 v was pretty safe).
Since the memory controller is build in the processor, the memory overclock depends now also on the processor temperature .
As conclusion, I can say only that core i7 is a new step in the development of desktop processors. Yes, the overclocking potential is low currently , but this may be fixed with time or luck . The use of HT technology and built-in memory controller considerably improved the performance in comparison with previous families processors.
Now this is a question of price since user have to pay not only for the processors. and motherboard Socket 1366 but also for the DDR3 memory ..
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