Oced i5-750 gaming issues


Long time since I posted on this forum, I am having some trouble.

I have an i5 - 750 oced to 3.6Ghz with a Biostar Tpower i55 board. It is stable in Prime95 but I occasionally get BSOD's in games for a number of reasons, but the most common is because of an ati system driver (according to crash dumps).

I am not sure what the problem is and was wondering if anyone on here could help. I originally thought it was the on board PCI-e controller that was unstable so I tried setting the QPI freq to that of the Uncore but this didn't seem to help.


Vcore - 1.240
VTT - 1.160
All others auto

43 answers Last reply
More about oced gaming issues
  1. How long did you run prime?
    Did you run it on small FFT (not the default one)?
    Stable run is 8-12 hours from what I've read.

    Also you can use multiple tress test like LinX. 20 loop when you increase clock/speed, 35+ loop for max stability test.
  2. increase VDIMM
  3. thanks for the responses.

    VDIMM is currently at 1.66v. But it was at 1.85v (stock for the board) and the problem was still occurring.

    I ran prime for about 5 - 6 hours on blend test so I could also stress the mem, I thought that would also indicate problems with the CPU is there were any.
  4. increase again VDIM max 2.7 V & godown Ratio
    increase Vcore too, do ... Vcore 1.37 can get 4Ghz above
    alway check your temp must above 70*C don't over cause damage your Proc and other hardware
    up up up.....
  5. Im guessing that its not that my QPI and uncore freqs were not the same then? Ok cool thanks, I will try all of these! :)


    Increase VDIMM? Really? My BIOS shows values higher than 1.85v in red. So is it safe to run mem on that high a voltage for constant use? Its the same with the Vcore. I know that i5's sometimes require even 1.4v for 4.Ghz, but this is 3.6GHz, didn't think it would need to be that high?
  6. don't worry abaut DDR2 it much higher Volt max 2.7 must with HSF different with DDR3 standard Vdim 1.5 can OC max Vdim 1.7~2 (HOT)
    if your mobo Good for Oc 1.4 too high for 4ghz , always check temp under 70*C
  7. OC must step by step by patient.... don't use HSF Stock Cooling use Aftermarket
  8. ok so I am safe to run my DDR3 with anything up to 2v? But that would be pretty hot? I will try but I think the VDIMM is ok, its pretty good RAM.

    My temps are currently 72 degrees under prime load with Akasa Nero heatsink.

    Should I only be worrying about SmallFFT test? I thought blend would be more important to test the link between mem and cpu.
  9. Correction - temps are 62!
  10. Whoa whoa whoa!! DO NOT INCREASE THE VDIMM OVER 1.7!!!!

    Max spec is 1.65V... holy christ 2.7V would melt your computer
  11. IMO add a little more voltage to the VTT, try 1.18. There's some wierd thing I've read that VTT and VDIMM must be .5V or less different, which actually seems to be true.

    It's quite possible it's the RAM tho, but if it needs more than 1.7V then you're much better off just lowering the speed or raising the timings than increasing the voltage.

    What's the current base clock, what's the RAM speed and timings set to, and did you use turbo boost or not? I also doubt you'll have to disable EIST, C States etc, but it can cause issues so if you want, get stable with them off but try them turned on after that because they are good features.
  12. Oh and as for testing, I find Intel Burn Test to be the most complete and quick test to run. High stress setting, 10 passes should give an idea of stability

    Also, that ATI driver crash is generally not associated with the CPU stability. They've reported having fixed the issue in more recent driver releases, so you should definitely try 10.10 if you're not. It can also be a random issue between the drivers and windows, and sometimes a fresh windows install will fix it.
  13. Hey, here is some more info about my current setup besides the volts I mentioned above.

    The baseclock is 180, multiplier x20.
    The mem is at 1440,timings:
    CAS 9
    tRCD 10
    tRP 10
    tRAS 25

    I thought goin above 1.7v for the vDimm was too high, I have been running blend test on prime for 6 hours now and all is fine, surely that means the mem is fine?

    Hmmm I will try a new instal of windows also,currently running most 10.10 ati drivers.
  14. When running prime make sure you tell it to check for rounding errors(under the advanced menu in prime).

    Try Small FFTs it hits the cpu good and hard(without much memory testing, thats what memtest is for :)). At least over night.

    NEVER go over 1.65 memory(1.66 generally gives 1.65 on most boards)
  15. remember he use ( 4GB (2 x 2GB) OCZ PC2-8500C5 1066MHz DDR2 ) not DDR3 , DDR2 default 1.8 & DDR 3 Default 1.5 what do u think? check standard JEDEC
    DDR 2 to down volt cause hi latency cannot get OC maximum ..
  16. I5's with DDR2? do they make those?

    Nope they don't.

    Here ya go, clearly a DDR3 board



    His specs in the sig are for a different system.
  17. sorry anybody ... it mistake !
    let see old my massage :
    don't worry abaut DDR2 it much higher Volt max 2.7 must with HSF different with DDR3 standard Vdim 1.5 can OC max Vdim 1.7~2 (HOT)
    if your mobo Good for Oc 1.4 too high for 4ghz , always check temp under 70*C
  18. yes DDR3
    i wrong! sorry sory for any body mistake write and read..... make me nervous!
  19. Yea my bad my sig is out of data, I have updated it now.

    Ok I will try Small FFT with rounding errors. In the past tho, I have just run small FFT tests and found the CPU to be stable but then when running a blend test I find prime to fail.

    @ Wolfram23: I also have turbo boost disabled aswell as all C-States and Intel Virtualisation Tech (whatever that is).
  20. If you fail under blend, look to the memory.

    Did you drop the memory multiplier when you bump the cpu speed. If not, you can push the memory past its spec speed(as the board has it in spec at stock).

    Please grab cpu-z and lets see your memory tab as well as your spd tab.

    You can host those images on http://imageshack.us/ or your favorite image host
  21. At 1440mhz and 9-10-10 timings I doubt there could be memory issues, unless there's general compatibility problems with the mobo.

    Have you tried running either Memtest86+ or Intel Burn Test?
  22. Hey guys,

    No response for a while as I have been carrying out all the advice that you guys have given me.

    First off here are some shots of the memory and SPD tabs from CPU-z:



    Here again is my current settings:

    BCLK = 180
    Multi = x20
    Vcore = 1.232v
    VTT = 1.160v
    VDIMM = 1.166v
    All rest is on auto.

    With these settings I have run small FFT and blend tests on Prime both for 6 hours, 20 tests with memtest and 10 tests with Intel Burn using both standard and maximum test levels, all of which passed. So I guess I am stable.

    I still think that because this BSOD only occurs in games that it might have something to do with the integrated PCI-E controller. To get this stable I guess I need to increase Vcore?

    The only thing left to do now is what Wolfram23 suggested which is a fresh install of windows 7 and latest ATI (sorry AMD :P) drivers.

    On a side not, does anyone think I would be able to improve my mem speed/timings? Based on the CPU-Z screen shots above I would have thought that I could get things tighter, although I have read that the difference in real world performance between CL9 and CL8 is minimal, its all about getting to CL7.
  23. With a memory voltage of 1.65(1.66 on some boards) you can get at lest 8,8,8,24.

    You may be able to get it to 7,8,7,24. You will only be able to test that by setting it and running memtest86(or memtest86+) overnight.

    Does this problem occur if you revert to stock settings?
  24. I agree that 8-8-8-24 should be easy.

    Also you could try turning of PCIe Spread Spectrum if your mobo has that.
  25. I am not actually sure if the problem does occur at stock :P I have been trying to oc my CPU since I first installed it.

    I think I will try a new install of windows, cant hurt. I am a little confused about my Uncore frequency and my QPI frequency. I cant set the uncore, so I assume thats related to the current frequency of the chip, yet I can set the QPI frequency. I currently have it set to the same as the Uncore frequency, is this best for stability?

    Ok I have just set my timings to 8-8-8-24 and run ten runs of mem test, all seems ok. My BIOS sas that at 180 BCLK I can run mem at 1800MHz. To get this speed will I likely have to loosen the timings and maybe apply a small over volt?

    @wolfram23: I cant see the PCIe Spread Spectrum setting in my BIOS, whats that?
  26. The BSOD just happened again even though all the above is true. Crash dumps says it has something to do with atikmdag.sys.

    BCCode = 3b.

    Any ideas?
  27. Try reinstall ATI Drivers?

    BTW Uncore is the same as QPI (im pretty sure)
    Also, Uncore controls Memory, L3 Cache and QPI link and uncore voltage is Vtt. with higher bclk, qpi or ram speeds you will need more Vtt. Max safe Vtt is 1.35v.
    for with 180bclk and 1800MHz Ram u might need 1.2v+

    Peaks said:

    Here again is my current settings:

    BCLK = 180
    Multi = x20
    Vcore = 1.232v
    VTT = 1.160v
    VDIMM = 1.166v
    All rest is on auto.


    Im pretty sure 1.16Vtt is stock setting.
    And are you sure VDIMM is 1.166v??? that is way too low. should be 1.66v?
  28. hey,

    Yes, thats a type, my mem voltage is 1.66v (set in BIOS).

    If uncore is the same as QPI why do I have options to set the frequency of each? If they are so tightly linked then I guess I should be running them at the same frequency right?

    When I get home I will actually take a look at what my VTT is if I set it to auto, then base everything off that. Should I be worried if my motherboard is showing the voltage value in red/yellow? Obviously this means the value is approaching unsafe.
  29. That ati issue, it's some wierd thing with drivers... it's been fixed for most people but sounds like you're one of the unluckies who still has a problem.

    You might want to try Driver Detective just to see what needs updating. Sometimes it's easy to miss an update. You can check your files for free with this program, and google for them. I actually went ahead and payed for it, so it will download the updates too. It's not perfect but it works.

    Anyway, I'm thinking it must be a conflict with your drivers.
  30. When you refer to my virtual mem pool do you mean how much or do I have one?

    I have assigned my virtual mem pool to my storage drive as my primary drive is an SSD and I wanted to prevent loads of writing to it.
  31. For voltages, you just want to stay under 1.35v for Vcore and Vtt, under 1.9v for Pll and 1.65v or under for VDimm. I wouldn't worry too much if your motherboard shows voltages in red/yellow, as long as you stay under max voltages and temps are under 75-80C you will have no problem.

    {I think Intel upped max voltages for Vcore and Vtt to 1.4v for i5 750 http://download.intel.com/design/processor/datashts/322164.pdf}
  32. Right ok thanks.

    Just checked and at auto my VTT is at 1.354v. Isn't that a little high? lol - it would be better for me to just leave it at auto.

    My system is stable in Intel Burn and prime so I dont think I need to up the VTT any more from 1.160v (set in BIOS). Unless you guys think it possible for my system to be stable in torture tests but not in game?

    I am leaning more towards what Wolfram23 is saying about an ati issue. :(
  33. I agree with Wolfram23 as well. its most likely an issue with catalyst.

    But 1.16v for Vtt is too low for 1800MHz ram. Tbh, you don't really need your ram clocked that high. Maybe lower ratio and tighten ram timings. Otherwise you should need around 1.2Vtt to have it stable.

    If Vtt is too low, you will get cache and ram errors.
  34. My RAM is actually at 1442MHz 8-8-8-24.

    As I said before I really think that it is fine considering a MemTest, Intel Burn Test and prime95 all pass.

    Think I will try a new install of Windows and get latest ati drivers.

    Thanks all for help!
  35. So I reinstalled Windows and am using the latest ATI drivers but the crash has occurred again. Once in game referring to atikmdag.sys and once when downloading from steam referring to some important kernal file.

    This is with Vcore at 1.232v, VTT at auto (1.354v in BIOS) and VDIMM at 1.65v.

    Any more suggestions from anyone? Are my voltages still too low? My comp passes all stress test (prime, intel burn and memtest).
  36. I think your Vtt is too high. On my i7 860, i have it overclocked to 180Bclk 1440MHz on ram CL 7-7-7-21 and im only using 1.19V on Vtt.

    Not always the best to have latest drivers. More so when you have a older video card. uninstall catalyst and install 10.2 or 10.3
  37. ok. Previously I had my VTT set at 1.16v, so I set it to auto to see if this being low had something to do with it, but even at 1.354v, my PC still crashed.

    I will try 1.19v VTT considering you have same BCLK and RAM freq as me, but I know I keep saying this....it passes all stress tests doesn't that mean it is ok?

    I will also try rolling back the ati drivers, thanks.
  38. maybe hit Vcore up one notch. I like to do that after stress tests just to be safe.
    But i still think crashes are most likely caused by catalyst drivers......since it was happening to me about a week ago >.<
    My problem was pretty much the same. lol.
  39. I think I will also try running my PC at stock for a while, if the crash doesn't occur I think I can put it down to the oc, if it does, then yea...it must be ATI drivers.
  40. This problem isn't related to CPU stability. You passed all the tests then it's pretty stable. atikmdag.sys is a known issue.
    I googled it:

    Tons of threads about it.

    Unfortuantely I don't know of any miracle cure for it...
  41. yea thanks. Interestingly, I have been gaming a lot at stock for 2 days now and not a single crash.
  42. its for Vista but I have followed this as a potential solution:


    Of course there is always the possibility that my card is on the way out. Had it three years now.
  43. Well hopefully it keeps working for you!
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