IMC (Integrated Memory Controller) & Triple Channel DDR3
The basic difference between technology Core 2 Duo/Core2 Quad locate on IMC (Integrated Memory Controller). In Core2 Duo/Core 2 Quad, IMC locate in the chipset (X38, X48, P45, etc). This is cause the ability of throughput from the memory highly depending on the chipset ability. While the core i7, IMC move to processor than the chipset, so theoretically can work lighter and throughput memory speed is very past, because there is no need through the chipset (Northbridge).
Difference architecture Core 2 Duo/Core2 Quad between Core i7
Front Side Bus 1066, 1333 and 1600 MHz is known to the processor Core2 Duo/Core2 Quad switch into (Quick Path Interconnect) on Core i7. The speed of FSB that was speed up to 1.6 GT/s multiple to 6.4 GT/s. This is because speed of memory controller internal on CPU more effective than the memory controller on Northbridge, this is not added implementation Triple Channel DDR3 on the platform core i7. Although, the benefit or effect this triple channel DDR3 is still significant in the real implementation.
QPI (Quick Path Interconnect)
Additionally, the Intel core i7 return the implementation technology hyper threading (HT) or also known simultaneous Multi Threading (SMT). Total processor on core i7 equal 4 core unit and each core have a SMT, so the total is 8 threads on a processor core i7.
Bclk (CPU Host Frequency) & CPU Multiplier
QPI is a speed bus replacement FSB, if FSB is a data transmission track between chipset, processor and memory. QPI is simpler than FSB. QPI is a data speed transmission from processor to chipset. If previous we know Northbridge as a chipset to control the processor, memory and PCI-E track, than in core i7, chipset know with name IOH (Input-Output Hub) is in duty as input tracker and output from all system.
24 x 133 MHz = 3192 MHz (round to 3200 MHz)
Total clock or total frequency processor core i7 is a result multiple from CPU Host Frequency (Bclk) with CPU Multiplier (CPU Ratio). For example, a processor Core i7-965 Extreme Edition have a speed 3.2 GHz, this speed come from result of multiple 24 (CPU Ratio) with 133 MHz (Bclk).
24 x 150 MHz = 3600 MHz (3.6 GHz)
To change this setting in BIOS(Motherboard GIGABYTE EX58-extreme) entry to Sub Menu MIT. There have a choose frequency Blck from 1 to 1200 and CPU clock ratio from 1x to 44x (depend to type processor is use).
With change the Bclk (CPU Host Frequency) from 133 to 150, you will accept the processor speed 3600 MHz (3.6GHz). This value 400 MHz more height from speed processor standard Core i7-965 Extreme Edition.
Special for Core i7-965 Extreme, overlooking also can do with change value of the CPU Ratio or CPU Multiplier.
With change the Bclk (CPU Host Frequency) from 133 to 150, you will accept the processor speed 3600 MHz (3.6GHz). This value 400 MHz more height from speed processor standard Core i7-965 Extreme Edition.
Special for Core i7-965 Extreme, overlooking also can do with change value of the CPU Ratio or CPU Multiplier.
28 x 133 MHz = 3724 MHz (3.724 GHz)
With change the value of CPU Clock Ratio from 14 become 28, will get processor frequency 3724 MHz form standard speed 3200MHz. One again pay more attention, over clocking with change CPU Clock Ratio only valid for processor with type CPU Clock Ratio. For Core i7-920 and 940 CPU Clock Ratio can`t change to a higher value. Because the manufacturing Intel have lock CPU Clock Ratio. For Core i7-920 and 940, over clocking can only be done with changing the CPU Host Frequency (Bclk).
Remember, in condition overclock, stabilization factor system must to attention. Unstable can occur because many things, one of which resulted in the QPI speed increase (if Blck is increase), another factor is a DDR3 speed and Uncore frequency is increase participant from that standard.
QPI standard processor Intel Core i7-965 Extreme is 6.4 GT/s with a value Bclk of 2.66 GHz and DDR3 on speed 1333 MHz. See picture in below, if Bclk increase by 150 MHz will be impact on increase QPI frequency , UnCore and DDR3, this three component close and mutually dependent with Bclk. If one of three this component doing on ubnormal condition or speed is higher than standard and tolerance has through will be caused unstable in system. Example unstable system like restart without caused, can’t go into operating system, application often error and etc. To troubleshoot unstable system overlock, provide divider or ratio on each QPI component. Uncore and DDR3
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