Having trouble Overclocking

Hello, I've been trying to overclock and finally got to 3.33 ghz on the i5 750 2.66 ghz cpu. I have 4 gigs of 1600 mhz ddr3 ram but its pretty old so it requires 1.8V to achieve 1600. With 1.65, I can get 1333 mhz but this limits my overclocking. Do you guys know any way I can get a higher cpu frequency and still maintain 1333 mhz or lower. I tried cpu ratio 18 x 200 multiplier and ram set at 1200 mhz, but it BSODs right after setup.

Thank you for the help.
31 answers Last reply
More about having trouble overclocking
  1. Have you tried lowering your memory multiplier?
  2. The FSB:DRAM ratio? 1200, 1600, 2000 mhz at 200 frequency thing?
  3. I tried, I put 18 cpu multiplier, 200 blck frequency, cpu voltage 1.3, IMC 1.175, DRAM 1.65, DRAM frequency : 1200 but it failed to boot. Does anything look wrong?
  4. You have the right idea, just backwards..........try 180X20 and set your memory to (6x)1080.

    The higher the Bclk, the more voltage you will need, like QPI/VTT, PLL, VCORE, etc.
  5. does the BCLK determine how much voltage is needed, or is it determined by the total speed of the cpu. Example : 1.35V for 18 x 200 vs 1.35V for 20 x 200. Is it like that or does the 4.00 Ghz require more voltage?
    Another thing is, since I'm only increasing the BCLK frequency that means i only have to increase the core voltage right, not the ram and all that. If I do put it at 180, the memory frequency will either be 1080 or 1440 and isn't that way too low or way too high?
    Thank you for your help.
  6. Any time you change the Bclk you are changing the ram speed, but you know that already.

    When you raise the Bclk you are going to need more VTT (IMC) at the minimum, depending on how high you raise it you may also need more PLL, PCH and Vcore. That's why it's easier to obtain a stable OC with a lower Bclk, giving you lower voltages and a cooler running cpu and computer. And yes when you go from 18X200 to 20X200 you will need more vcore.
  7. I heard that its best to leave PLL and PCH on auto. Is this true? And can you take a look at this http://www.tomshardware.com/reviews/core-i5-750-overclock,2438-6.html. What's CPU-Z VT and CPU VTT and BIOS VCore. How do they differ?
    Thank you for your help.
  8. I'm guessing you mean CPU-Z core voltage reading, that's the vcore.
    CPU/VTT (I'm guessing your Bios is referring to QPI/VTT) is your Quick Path Interconnect voltage or acually DMI voltage.
    Your Bios vcore is the main processor voltage.
    If your wondering why the difference between the Bios vcore and CPU-Z vcore reading, Google "vdroop".
    As for PLL and PCH being left on Auto, completely up to you but I would set them to the default values (1.8v @ 1.05v) so I didn't have to worry about them.
  9. Alright, Hows this sound :
    Ratio : 20
    BCLK Frequency : 180
    DRAM : 1080
    QPI Frequency: Lowest setting
    Core Voltage : 1.25V
    IMC voltage : 1.3V
    DRAM Voltage : 1.65V
    CPU PLL Voltage : 1.8
    PCH Voltage : 1.05

    I followed your ( 1.8 V and 1.05 V ) tip but add more juice on the PCH Voltage. I also used the overclocking guide i showed you ^ but changed the IMC voltage to 1.3V from 1.1. Why is it that theres can be stable on 1.1V but mine can't at 1.175? I havent tried this yet, just asking you to review it and see if its makes sense.

    Thank you for helping and responding pretty quickly.
  10. Well, that link didn't work for me.

    You shouldn't need 1.3v IMC but you can try it. If it's stable you can try to lower it afterwords.

    Looks like a good start.
  11. Can you explain to me what the IMC voltage directly relates to and the PLL and PCH as well. The DRAM Voltage, im guessing it relates directly to the ram frequency directly because I dont need to change it unless I go pass 1333. I got my cpu to 3.6 ghz but in order to do this, I had to use 1.275 V vs 1.25 V on many of the overclocking guides I've read. Does this relate to the bad ram that I have?

    Thank you for the help.
  12. Ooh, I just learned that even though my ram frequency is 1080, the out come is actually better because of the timings I think. Awesome.
  13. Ran Prime95 and got "FATAL ERROR: Rounding was .5 epected .4..." so i either have to increase V core or DRAM voltage right? I'm just scared about going past 1.65 on the DRAM because people say its dangerous. Whats your thought?

    Ty for help.
  14. OCing is a trial and error ordeal and will usually require more than one thing to be changed to optimize your OC.

    You can up the vcore a notch and test, the up the PLL a notch and test, then PCH, etc. to find what your processor and board want/need to be stable. At 3.6 Ghz it will probable only need the vcore though.

    Correct, don't go over 1.65v on the vdimm.
  15. Alright. Thanks, boosted the VCore to 1.3. What does the PLL and PCH voltage do. Example : Vcore - CPU. DRAM Voltage : Ram.

    Thank you for the help
  16. Ty
  17. Wow even after 1.3 i still get FATAL ERROR : Expected .5....Could this be anything other then the VCORE? Cause 1.3 should be more than enough for a 3.6 OC according to i5 750 OCing guides.
  18. Run Prime95, small FFT and see if that passes, if it does then it's probably the ram.

    You can run Memtest also to be sure.
  19. Alright ill try that.
  20. theres also i nice little site here with information on step by step overclocking if anyone is interested http://f13975gfs8pyjz3q83xe4s6uat.hop.clickbank.net/
  21. Thanks
  22. I don't think you should click the link. From what I've read its a phishing site. DONT FALL FOR IT or maybe im wrong, but just a warning. NT buddy.
  23. lol i suppose it does look like that doesnt it, its not just a video/ ebook tutorial


  24. lol. Iono man, just saying i dont trust it. Looked it up before i clicked it thats why. Flagged as phishing site, so Im not gonna take the risk. Ty or Nt i dont know.
  25. Hey RJR, I finally did the FFT test and it passed. That means that its the ram is the problem right? What do i do to fix this, what voltage do i increase.

    TY for the help
  26. If you don't understand the mechanics and consequences of overclocking... then you SHOULD NOT BE OVERCLOCKING!

    The first thing you need to be able to do is to shed the EXTRA heat that will be generated by your processor when it is overclocked. The only way to do that is to improve the existing cooling your processor has.

    So, No. There is no way you can overclock your processor without buying a new cooler. especially considering the temperature conditions you are operating within.
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  27. Already have a cooler, everything under 80 C.
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