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Technical training
The I7, processor Intel
Released in 2008, I7 is a computer processor
quad-core desktop applications but also server specific characteristics compared
to its predecessors as the Core2 Duo. It is based on an entirely new
architecture, Nehalem and accepting modes 32 and 64 bits following the
instructions of Intel EM64T (equivalent to AMD's AMD64 ISA).
First feature, the I7 directly integrates the
memory controller (like the Athlon 64 and Phenom since 2004) but on 3
channels. It manages DDR3 Ram until 1066 MHz Dual Channel (so 6 memories modules). This reduces the latency memory access since there is the
Northbridge chipset as an intermediary. The socket is new (LGA1366) with a new
system for setting the cooler.
The second characteristic is the Management
of the 4 cores integrated into the microprocessor. In the Core 2 Duo, clock
speed is identical for all present Core. In these new processors can handle
frequencies of each individual core, including one or more overclock core during
a low period if others do not work or less. It is the Turbo mode under
the IDA used in some models of processors for notebook PCs.
The third feature is related to the cache
management. In a Core2 Duo processor, two processors are finally joined
together simply with one another as in the diagram cons with well-defined L2
caches. Instead, I7 handles 4 processors as a single whole.
Found
for each processor L1 cache of 32 KB for instructions and 32 KB for data (same
as Core 2 Duo) L2 cache integrated into each Core 256 KB, but especially a
shared cache of 8 MB is in Wholesale 2 MB per core. The L1 and L2 caches are
also copied to the L3 cache to allow a real sharing of information. This also
allows the sharing of data in different cache among all the hearts of I7.
The fourth characteristic is linked to a new
bus, QPI (QuickPath Interconnect) similar to Hyper-Transport AMD manages
external communications to the northbridge but perhaps also in multiprocessor
future developments. This new bus connects the CPU to Northbridge with loan of
4.8 gigabytes transfer per second to the bus via a total of 20 bidirectional
channels, ie effective data rate of 4.8 X 20 / 8 = 12 GB / s (a 6.4 Giga
transfers - GT / s - is announced).
It could be just the processor but incorporates
many other surprises as integrated virtualization. Necessary for future
applications but especially retrour of the Hyper-Threading implanted in
the latest Pentium IV and then removed in the Intel Core used which
ultimately improved architecture of a Pentium III, so difficult to modify.
Hyper-Threading allows to manage two logical processors in one heart to win (if
the application is designed for) 30% performance.
At
level chipset, only the X58 Intel is currently on the market. SLI technology can
be implemented on motherboards as the chip accepts a 2-channel 16-port
PCI-Express 2.0 mode (more than 6 ports on the Southbridge (the Intel ICH10 in
this case)).
The first three versions are:
i7-950, frequency 3.06 GHz, L3 cache of 8 MB with QDI 4.8 GT / s
i7-940, frequency of 2.93 GHz, L3 cache and 8 MB QDI with a transfer rate
of 4.8 GT / s
i7-920 is identical but with a frequency of 2.66 GHz.
i7-960 with a frequency of 3.2 GHz (10-2009)
and the Extreme Edition series (June 2009), the transfer bus speed is increased from 4.8 Giga transactions per second at 6.4.
i7-975 with a frequency of 3.33 GHz, but especially one who spends GTS 6.4
i7-965, identical but with a frequency of 3.2 GHz
Then come along with the output of the I5 in September 2009 and using the Socket
LGA1156 and the P55 chipset (therefore some limitations since it uses it the
"old bus" DMI to connect southbridge is the P55) but also
opportunities turbo modified: therefore less efficient with no Dual PCI
Express for video cards.