Increasing i7 975 multiplier?

Hi, I'm trying to overclock my i7 975 Extreme.

I've read that the 975 has an unlocked multiplier, but my multiplier caps at the stock value of 25. I can only overclock right now by increasing the FSB but the system is stable at 3.8 GHz with default voltage and good temps (40C idle, 70C load). I've tried changing Hyperthreading, Turboboost, and power-saving options.

Is something wrong or do I actually have to "unlock" the multiplier? Thanks!

OS: Windows 7 Ultimate x64
CPU: Intel Core i7-975 OC'd to 3.8GHz (25 multiplier, 152 FSB, default voltage, HT and TB off)
Mobo: Intel DX58SO BIOS v. 5456
RAM: Corsair XMS3 6GB DDR3-1600 (set at ~1500 mHz)
GPU: Radeon 6870 1GB
HDD: G.Skill Phoenix Pro 60GB, x1 W.D. Caviar Blue 640GB 7200 RPM, x1 Samsung F4 2TB, x2 Samsung F3 1TB
PSU: Kingwin Lazer 1000W
Cooler: ZALMAN CNPS9900ALED 120mm
7 answers Last reply
More about increasing multiplier
  1. Not sure about the unlocking aspect, but beyond 4GHz, high temps could be an issue - watch the temps closely. The clock speed Vs temp rise is not linear; its exponential.
  2. if you have the 975 you should have the unlocked multiplier. Witch means that you should be able to put it at 30 if you want..hence the "unlocked" part. did u try entering the #s manually like manually entering the value that you want??
  3. Thanks for the replies! Like I said, I can overclock fine by increasing the FSB but I'm just curious as to why the multiplier can't be increased over 25. The DX58SO BIOS doesn't let me manually enter in values either, I can only use "+" and "-" to change the multiplier.
  4. have u tried hitting the "-" all the way down till "x1" and then hitting down again to see if it goes in a loop? you have the latest BIOS updates for your mobo? that could be your issue right their!!!
  5. The multiple loops from x12 to x25 and I have the latest BIOS from Intel. It might just be the mobo limiting the CPU. :(
  6. it has to be a setting some where because if you look at the mobo on inel's website it supports the 980X witch is the 6core

    also chech this you see an option that says UCLK multiplier??
  7. Try this, entered manually.

    BLCK = 150
    PCIE = 100
    CPU Ratio = 28
    QPI = 7.200GT (I had to set this higher in my BIOS than it actually is. Windows see's it @ 6.4GT, which it stock.)
    DRAM = 750MHz DDR3 1500 (stock is DDR3 1600 @ 9-9-9-27. DDR3 1500 is @ 8-9-9-26.)
    CPU Voltage = Overdrive Offset @ 0.12500V
    VTT Voltage = 1.340V
    CPU PLL Voltage = 1.90V
    Intel Speedstep & C-State are both Disabled.
    Hyperthreading is Enabled, Turboboost is Disabled.

    Hope this helps..
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