# [Solved]Prime95 "FATAL ERROR: Rounding.." - No OC



## Kokoro1280

So i posted a few weeks ago about BSOD's and it turned out to be having a bad set of RAM. I just got the replacment yesterday and i went on to test with memtest86 for 7 hours with no errors.

So earlier i loaded up prime95 blend test and within an hour it failed with the error message:
Note im not OCing anything.

[Wed Mar 20 12:50:01 2013]
Self-test 12k passed!
Self-test 12k passed!
Self-test 12k passed!
Self-test 12k passed!
[Wed Mar 20 13:08:015 2013]
Self-test 448k passed!
Self-test 448k passed!
Self-test 448k passed!
Self-test 448k passed!
[Wed Mar 20 13:23:32 2013]
Self-test 8k passed!
Self-test 8k passed!
Self-test 8k passed!
Self-test 8k passed!
[Wed Mar 20 13:37:37 2013]
FATAL ERROR: Rounding was 0.5, expected less than 0.4
Hardware failure detected, consult stress.txt file.
Self-test 512k passed!
Self-test 512k passed!

I ran prime95 small fft's with no errors, it only seems to happen with blend mode.

This is my setup

CPU - i3 3220 Ivy Bridge @ 3.3GHz (Stock settings)
RAM - G.SKILL Ares Series 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1866 9-10-9 @ 1.5v
Mobo - ASRock Z75 Pro3
GPU - EVGA GTX 550Ti

I've went into bios and made sure ram settings were correct. I've searched google and most of the answers point to ram first or upping vcore for overclocking. I am not trying to overclock though so any help would be much appreciated!


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## frogger4

That's interesting. I've seen some cases where memtest says everything is okay, but there is still a RAM problem. Here are some steps to nail down what's going on:
- Drop the memory down to 1600MHz (same timings), and run Prime95 again.
- If it crashes again, drop the CPU multiplier down by two notches and run Prime95 again.

Even though neither of those "should" be problems, I think it is important to be able to rule them out first.

Edit: To clarify, I don't mean either of those as long term solutions, but just as a way to get a better idea of what the problem is.


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## Kokoro1280

thanks for the reply =)

The PC isn't crashing or bsod'ing. Just that error in the prime95 window. Also the RAM is factory 1866 so is it alright to run it at a lower speed?
for the multipier, its not an unlocked cpu so under CPU Ratio its currently set to auto. The other option is 'All Core.'


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## frogger4

Quote:


> Originally Posted by *Kokoro1280*
> 
> thanks for the reply =)
> 
> The PC isn't crashing or bsod'ing. Just that error in prime95. Also the RAM is factory 1866 so is it alright to run it at a lower speed?
> for the multipier, its not an unlocked cpu so under CPU Ratio its currently set to auto. The other option is 'All Core.'


Yeah, the reason I suggested trying the RAM at 1600MHz is that I have some RAM that is quite functional (no errors), but just isn't quite stable at its rated speed. It's perfectly fine to run it a lower speed than advertised - You probably selected the XMP setting which sets the RAM to its regular rated speed, but you can also choose the speed manually.

And for the CPU, you can actually change the multiplier on locked chips up to the maximum of 33 in your case (meaning you can underclock but not overclock). To do so, set it on All Core rather than Auto, and then you will be able to type in 31 for example. At any rate, there is no reason to try this until it is known for certain that the RAM is good.


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## Kokoro1280

yeah did have a XMP profile selected. I'm running prime now with it at 1600mhz so we'll see how it turns out.


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## liamstears

Quote:


> Originally Posted by *Kokoro1280*
> 
> yeah did have a XMP profile selected. I'm running prime now with it at 1600mhz so we'll see how it turns out.


If you don't get any errors select your xmp profile again but then just boost your voltage on your ram slightly that should fix it or if not maybe slightly boost imc voltage but I would think boosting ram voltage slightly will do

Or just check what voltage it's set to

It may be your ram is rated at 1.65v at 1866mhz but your motherboard is setting 1.5v


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## frogger4

Quote:


> Originally Posted by *Kokoro1280*
> 
> yeah did have a XMP profile selected. I'm running prime now with it at 1600mhz so we'll see how it turns out.


Cool, I'm interested to see how that goes!


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## Kokoro1280

It's rated 1.5v as far as i know. Sorry for not linking the ram though









G.SKILL Ares Series 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1866

It's been going for a little over an hour now with no errors. Would it be alright to leave it at 1600 long term if everything seems alright? ( the only reason i bought 1866 is because it was quite abit cheaper than its 1600mhz version at the time haha)


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## SoloCamo

Quote:


> Originally Posted by *Kokoro1280*
> 
> It's rated 1.5v as far as i know. Sorry for not linking the ram though
> 
> 
> 
> 
> 
> 
> 
> 
> 
> G.SKILL Ares Series 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1866
> 
> It's been going for a little over an hour now with no errors. Would it be alright to leave it at 1600 long term if everything seems alright? ( the only reason i bought 1866 is because it was quite abit cheaper than its 1600mhz version at the time haha)


No harm in lowering it, just lower performance (though to be honest, you'd never notice it). I'd try to put it back at 1866 then bump the volts by a hair. For example from 1.5 to 1.55 should alleviate the issue. If not, keep the volts 1.55 and loosen the timings slightly.


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## frogger4

Quote:


> Originally Posted by *Kokoro1280*
> 
> It's rated 1.5v as far as i know. Sorry for not linking the ram though
> 
> 
> 
> 
> 
> 
> 
> 
> 
> G.SKILL Ares Series 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1866
> 
> It's been going for a little over an hour now with no errors. Would it be alright to leave it at 1600 long term if everything seems alright? ( the only reason i bought 1866 is because it was quite abit cheaper than its 1600mhz version at the time haha)


Yep, that would work fine. Another option that will likely work is having it at the regular 1866MHz, but increasing the DRAM voltage to 1.55 V. My suspicion is that the RAM will work perfectly at 1600MHz with 1.5V, or 1866MHz with 1.55V, but that is something you'll have to play around with.

Hope this was all helpful!


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## SoloCamo

Quote:


> Originally Posted by *frogger4*
> 
> Yep, that would work fine. Another option that will likely work is having it at the regular 1866MHz, but increasing the DRAM voltage to 1.55 V. My suspicion is that the RAM will work perfectly at 1600MHz with 1.5V, or 1866MHz with 1.55V, but that is something you'll have to play around with.
> 
> Hope this was all helpful!


Our posts were identical, even down to the volts and only seconds apart


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## Kokoro1280

Ah alright i will try that. Im gonna run this for a couple more hours to make sure its fine @ 1600 though and then put it back to 1866 with 1.55v. I've never really tweaked volts so its kind of new for me. Will update later though, thanks for the info so far!

edit: ran it for 2hrs 21mins. Gonna try 1866 now with 1.55v


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## Kokoro1280

DRAM Voltage: 1.550v

is that right? Just want to be sure









Edit: nevermind got it lol.

Edit 2: wanting to verify the ajusted voltages in windows. What program shows that?

Edit 3: running at 1866Mhz @ 1.550v for 5 hours now with no errors. Gonna sleep and might as well go the 12 haha. Seems fine so far though.

Final Edit: Ran a full night of prime and everything went smooth. Thank you so much for the help guys!


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## SoloCamo

Excellent, glad to hear it







And no problem at all of course


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## frogger4

Quote:


> Originally Posted by *Kokoro1280*
> 
> DRAM Voltage: 1.550v
> 
> is that right? Just want to be sure
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Edit: nevermind got it lol.
> 
> Edit 2: wanting to verify the ajusted voltages in windows. What program shows that?
> 
> Edit 3: running at 1866Mhz @ 1.550v for 5 hours now with no errors. Gonna sleep and might as well go the 12 haha. Seems fine so far though.
> 
> Final Edit: Ran a full night of prime and everything went smooth. Thank you so much for the help guys!


Haha good work!
You can verify speed with CPU-z memory tab (it actually shows 1/2 of the effective speed (the one you set)). That will also allow you to verify the timings. I'm not sure how to check the memory voltage within Windows, but yes 1.550 is right.

And, yay! Problem solved.


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