Guide – Overclocking Prosessor Intel Core i7 Part II

QPI Link Speed

The values of QPI Bus get from result multiple Blck and QPI Multiplier (QPI Link Speed). The condition Blck is running on height speed from standard speed (overclock), QPI Bus will also participant to everclock. QPI Multiplier on default condition for Core i7-965 XE is 48, with Blck 133 MHz. So 48 x 133 MHz = 6.384 GT/s (round to 6.4 GT/s). While on processor Core i7 -920 and Core i7, QPI Bus is lower, equal 4.8 GT/s, get from multiple 36 x 133 MHz, that mean Core i7-920 and 940 have QPI standard multiplier equal of 36.

When overlock thought Bclk, where speed Bclk up from normal condition, example 150 MHz, QPI Bus to 48 x 150 MHz = 7200 (7.2 GT/s), some time occur error unstable system on the QPI Bus condition height like this. To resolved this problem and increase stabled system, you can increase voltage in VVT and PLL. This is can be done from bios, in submenu MIT choose QPI PLL Voltage or QPI VTT.

Note: This voltage can only done when you use cooling non standard Intel or 3^rd party cooling with height performance. Increase step by step voltage and always testing stabilization system with benchmark.

If choose to voltage always risky, is another way than can be done is to change or inherit value QPI Link Speed, in BIOS serve some from multiplier AUTO, x36, x44, x48 and Slow Mode.

Besides that, with decrease QPI Link Speed, result Bclk and total clock processor will also be higher because QPI bus still in the limit of tolerance.

Table QPI Bus can see below with various possibilities Blck, CPU Ratio and QPI Link Speed.

Uncore Frequency

Uncore Frequency related with L3 Cache speed and also have close ties with QPI and IMC. The higher the Frequency Uncore performance will be high. Although at the same speed processor. The following picture will explain the position Uncore on a Core i7 processor.

Uncore Frequency get from result the square: Bclk x Uncore Multiplier. In the standard condition, Bclk 133 MHz, multiplier Uncore equal 12, so Uncore Frequency become to 1600 MHz. Options Uncore multiplier provided in the BIOS from 12 to 30. If you want to increase the speed Uncore, you change the multiplier value Uncore to a larger number. Uncore limitation for cooling air or water-based (heatsinks Fan or Watercooling) about 4000 Mhz to 4100 MHz. While, if using subzero cooling (Dry Ice, Phase Change or Liquid Nitrogen), Uncore limitation on the number 4500 MHz to 4600 MHz.

Memory Multiplier

Important factor in the latest Intel Core i7 overclocking is the memory multiplier. High-speed processor (clock, red), will have performance that is not consistence, if it is not followed by a high-speed memory also, Here the memory multiplier role. Two processor system with the same speed and same clocknya can difference in terms of performance because of differences in the frequency of memory.

This table is calculation divider and speed of memory. The motherboard used is GIGABYTE EX58 Extreme, so this table use only for at the motherboard.

Multiplier Memory can change from the BIOS option on the System Memory Multiplier in the sub menu MIT. The multiplier services 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, speed of memory running at 1333 MHz. This means that the memory multiplier to work on 10.0. If you want to increase system performance without increase the bclk or CPU Ratio. Increase only memory multiplier to multiplier number is higher. To achieve this, of course, required that is capable of DDR3 memory to run higher.

Example: A system based on the Intel Core i7 use Triple Channel DDR3 memory 1600 MHz. When install with the standard conditions, the BIOS still recognizes it as DDR3-1333, memory multiplier is running on multi 10. It so excessive, memory speed as higher is only running at 1333 MHz. To be able use of speed in 1600 according to the manufacturer standardization memory, memory multiplier can be changed to 12:00, so the speed of memory running at 1600 MHz (133 MHz x 12.0). Speed will also automate changed, when Bclk increased. Example Bclk on the speed of 150 MHz with the memory multiplier 12, the total speed of the memory will be a 150 Mhz x 12.0 = 1800 MHz.

Overclocking Processor Inter core i7 part I