OCing 2500k Question

Hi everyone,

I've OCed to 4.5 GHz right now and when I run Prime95 I get this error: "FATAL ERROR: Rounding was 0.5, expected less than 0.4 | Hardware failure detected, consult stress.txt file" I couldn't find the stress.txt file so I decided to try and find an answer on here.

This only happens for one of the workers, not all of them. All temperatures are fine (no higher than 60 C).

Does this just mean that I've increased the multiplier too much? Or is there something wrong with one of the parts?


MSI p67a - g45
i5 2500k
cooler master hyper 212 plus
lian li pc-k62

Any input/advice is much appreciated! Thanks for your help!

EDIT: Never mind! Dropped the multiplier down to 44 and have been running Prime95 for an hour without any problems so far.
8 answers Last reply Best Answer
More about ocing 2500k question
  1. Increasing the CPU voltage would likely have allowed you to run at 45x multiplier, but if you're cool with 4.4GHz just leave it there.
  2. Are there any consequences with pushing your cpu to the max? I realize 4.5 GHz obvioulsy isn't the max but I'm sure 5 GHz would be given my cooling. This is my first time OCing and I'm just concerned with durability issues. I'd like to be able to use this for another four years or so. Do you think it would be worth it to gain another 600MHz or so? Or is it more of a bragging rights kind of thing?
  3. As far as I know, there are no programs or games that won't run on maximum settings with a 4.5GHz Sandy Bridge processor. By going higher, you won't gain any real benefit except for E-peen.

    A notable exception to that would be programs like SETI@Home, Einstein@Home, and other BOINC programs. Those will use every last MHz you can give them.
  4. Hey smitty, I started overclocking my PC last night and got exactly the same result :)

    When I set the multiplier to 45 I get a single worker error in Prime95, but when set at 44 I get no issues. CPU-z shows 1.260 v and coretemp max was 62

    I followed mrface's guide in the main thread, but made minimal setting changes;
    Disabled C1E Support & Enabled Internal PLL Overvoltage

    Leaps > If I want 4.5 stable, is it as simple as increasing the CPU voltage in the bios and testing? I read the other threads and your comments indicate that 1.3-1.35 is needed for 4.5 stable?

    Smitty > Sorry to hijack your thread, but thought the answer could be used by both of us :)
  5. Best answer
    My recommendations for most people are as follows:

    Keep all settings at defaults/Auto other than the particular ones needed for overclocking. That means leaving C1E and all of the CStates settings enabled (or Auto) and Internal PLL Overvoltage disabled. You shouldn't need the overvoltage until about 4.7GHz anyway.

    So, for 4.5GHz:
    1. Change multiplier to 45x
    2. Save and exit

    Boot into Windows and fire up Prime95. Use a monitoring program to check the CPU voltage. If it's 1.3v-1.35v, great, leave it alone. If it's below or above the range, you will need to adjust the CPU voltage manually using the Offset mode. Also monitor the CPU core temps -- if they go above 75ºC, you need a better CPU cooler.

    Using my recommendations will allow you the best of both worlds -- your CPU will idle at 1.6GHz when you don't need full power, and it will instantly boost up to 4.5GHz when horsepower is needed. Intel designed the CPUs to operate this way, even when overclocked.

    The other method where C1E, SpeedStep, and CStates are disabled means the CPU is running at full speed all of the time. Since the vast majority of the CPU's time is spent idling, this is a colossal waste. Your electric company will love you, and mother earth will try to kill you every chance she gets. lol For the record, I run my machine with these settings -- but then I also run the CPU with voltage that will end up killing it.

    Since you already know you are below the range, you will need to adjust it using Offset mode for the CPU voltage.
  6. You really HAVE to run Prime 95 for more than an hour to test for instabilities. I would say an easy 10 hours

    You'll have to test it that long for 4.4, and tweak the voltage if you want 4.5
  7. @bearclaw99

    I'm aware of that, thanks though. I ran Prime 95 for roughly the next 15 hours to make sure it was stable. I had just asked my question because I was receiving an immediate hardware error that was concerning me.


    No problem! We're all here to learn right?


    Thanks for pointing out the power saving options. I turned them off because of what I read in the overclocking guide here but I will definitely turn them back on now to save some energy!
  8. Best answer selected by smitty10.
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