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View Single Post - Intel Core i7 920 Overclocking Introduction Guide on X58
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Old 01-01-2009, 03:48 PM   #3
eva2000
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Guess not all folks have the basics or under Core i7 cpus, so even more basic explanation might be need. I'd start with reading this bit out dated but useful nonetheless thread at http://www.xtremesystems.org/forums/...d.php?t=205688

default Multipliers on 965XE
133 x 24 = 3200MHz CPU
133 x 24 = 3200MHz QPI (6.4GT/s)
133 x 20 = 2666Mhz UnCore
133 x 10 = 1333Mhz Mem (DDR3 1333)

default Multipliers on 940
133 x 22 = 2933MHz CPU
133 x 18 = 2400MHz QPI (4.8GT/s)
133 x 16 = 2133Mhz UnCore
133 x 8 = 1066Mhz Mem (DDR3 1066)

default Multipliers on 920
133 x 20 = 2666MHz CPU
133 x 18 = 2400MHz QPI (4.8GT/s)
133 x 16 = 2133Mhz UnCore
133 x 8 = 1066Mhz Mem (DDR3 1066)
So when raising bclk to overclock cpu, you're effectively raising cpu core mhz, qpi frequency, uncore frequency and memory frequency. As you raise those 4 components you need the right amount of
  1. vcore for cpu
  2. cpu vtt (uncore) for qpi frequency and bclk
  3. vdimm for uncore frequency and memory frequency.

Latest version of CPU Tweaker which is read only application for i7 will illustrate the effects of rising bclk from 133 to 214 bclk and how the CPU, QPI, Uncore and Memory frequencies change. Update: CPU Tweaker v1.1 has allowed subtiming changes for X58 boards from Gigabyte, EVGA and now with latest DFI 4/28 bios for UT X58.

CPU Core = 19 x 212bclk = 4028Mhz
Uncore = 22 x 212bclk = 4664Mhz
QPI = 18 x 212bclk = 3816Mhz
RAM = 4x 212bclk = 848Mhz (bios will be 8x 212bclk for DDR3-1696Mhz)


Last edited by eva2000; 21-12-2009 at 02:12 PM.
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