QPI Speed Link.
The value obtained from the QPI bus Bclk product with QPI Multiplier (QPI Speed Link). Bclk conditions running at higher speeds than the standard (overclock), QPI bus will also teroverclock. QPI Multiplier on the default condition for the Core i7-965 XE is 48, with Bclk 133 MHz, then 48 x 133 MHz = 6384 GT / s (rounded to 6.4 GT / s). While the -920 processor Core i7 and Core i7, lower QPI Bus, the 4.8 GT / s, obtained from the multiplication 36 x 133 MHz, which means that Core i7-920 and 940 have a standard for QPI Multiplier 36.
When to overclock through Bclk, where the speed is increased from Bclk normal conditions, such as 150 MHz, QPI bus to 48 x 150 MHz = 7200 (7.2 GT / s), sometimes occurs in conditions of instability of the system this high QPI bus. To overcome these problems and improve system stability, can you can increase the supply voltage (voltage) at the VTT and PLL. This you can do from the BIOS, the MIT submenu select QPI PLL VTT Voltage, or QPI.
NOTICE: This voltage change can only be done if you use non-standard Intel cooling or 3rd party cooling with high performance. Raise the voltage little by little, and always test the stability of the benchmark system.
If the option is too risky to raise the voltage, other ways that can be done is to change / lower the value of QPI Speed Link, the BIOS is provided a multiplier ranging from Auto, x36, x44, X48 and Slow Mode.
In addition, by lowering QPI Speed Link, Bclk acquisition and the total clock processor will also be higher because QPI bus is still within the limits of tolerance.
Below is a table can be seen QPI bus with possibilities Bclk, CPU Ratio and Speed QPI Link 




Uncore Frequency

Frequency related Uncore speed L3 cache and has close ties with QPI and IMC. The higher the frequency Uncore the higher performance, although at the same speed prosessornya. The figure below will explain the position Uncore on a Core i7 processor.

Frequency Uncore obtained from the multiplication: Bclk x Uncore Multiplier. In standard conditions, 133 MHz Bclk, Uncore Multiplier value 12, so be Uncore Frequency 1600 MHz. Multiplier Uncore options provided in BIOS from 12 to 30. If you want to increase the speed Uncore, you just change the multiplier value to Uncore greater numbers. Uncore limitations for cooling air or water-based (or Watercooling Heatsink Fan) about 4000 MHz to 4100 MHz. Meanwhile, if using subzero cooling (Dry Ice, Liquid Phase Change or nitrogen), there are limitations on the number Uncore MHz to 4500 MHz 4600.

Memory Multiplier

Last important factor in overclocking the Intel Core i7 Memory Multiplier. High-speed processor (read: clock), will have an uneven performance if not accompanied by a high-speed memory, too. Here memory multiplier role. Two systems with the same processor and same speed clocknya can differ in terms of performance due to differences in memory frequency.

Below is a table speed of calculation and memory divider. The motherboard used is GIGABYTE EX58 Extreme, so the table is intended only for the motherboard 




Memory multiplier can be changed from the BIOS on the option in the System Memory Multiplier in the MIT sub menu. Multiplier provided starting from 6.0, 8.0, 10.0, 12.0, 14.0, 16.0 and 18.0. Suppose Core i7-965XE with Bclk running at 133 MHz standard conditions, memory running at 1333 MHz speeds. This means working memory multiplier at 10.0. If you want to increase system performance without increasing the speed or CPU Ratio Bclk, just raise the memory multiplier to figure the higher multiplier. To achieve this required course DDR3 memory that can run higher.

EXAMPLE: An Intel-based systems using Core i7 Triple Channel DDR3 memory 1600 MHz. When attached to the standard conditions, the BIOS will still recognize it as DDR3-1333, a working memory multiplier on multi 10. How mubazirnya, high-speed memory is only running at 1333 MHz. To be able to take advantage of the speed of 1600 according to standardized memory manufacturer, memory multiplier can be changed to 12:00, so the speed of memory running at 1600 MHz (133 MHz x 12.0). Memory speed will also change, if Bclk raised. Example Bclk at speed with 150 MHz memory multiplier 12, the total available memory speed will be 12.0 x 150 MHz = 1800 MHz.

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