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CMZ16GX3M4A1600C9B only 1,2 and 3 ok... 4 = no post


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I started a new build the other day and have got the CMZ16GX3M4A1600C9B set. I found that 1 or two sticks work fine. With 3 sticks prime95 would stop after a few secs so I tested with Memtest and it gave many many errors but upping the voltage to 1.8V from the stock 1.5V brought the errors down to 0 and prime 95 could now run for ages (until I stopped it).


With 4 sticks the computer doesn't even boot and I have to reset cmos and use the memok button on the board to get the pc going again. All my components are new except the optical drive...


I also updated the mobo bios to the latest...


Could any of you guys suggest what I can do?


I am a bit afraid of upping the voltage any more as 1.8 seems like far enough already!


Your responses would be really appreciated!

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Thank you very much for the replies guys!!!


The 1.8v is for the ram not cpu, all chips work and test fine on their own, its just when I add more they require voltage increase and then at 4 no post...




Ok after some reading I kind of get the last posts meaning... Increasing the DRAM voltage increases the CPU voltage?


I have tested each of the ram sticks individually and the computer can boot and stay stable on each individually... With memtest86 how long should I test for because I left it for 35mins on the first stick I tested and it didn't seem to ever want to finish so I did! When I had 3 sticks in I tested and within a few seconds there were 100s of errors... After voltage increase there were none fr the few mins tested.


Please advise guys :)

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Ok after some reading I kind of get the last posts meaning... Increasing the DRAM voltage increases the CPU voltage?

No , but Intel is really adamant about using 1.5v memory on the Sandy's. Too much voltage can fry the memory controller that now resides on your CPU instead of the MB.


Those modules should run at 1.5v period. Since they alll pass memtest i would say it's either the MB or the CPU. My guess would be the MB since they all work by them selves and not together. But then again 1.8v may have damaged the CPU too. *shrugs*

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Thank you for your reply!


I apologise about the ambiguity of me saying all tested fine on their own.. I only ran mem test on 1 module and then 3 (which failed till I upped the voltage and tested for a short min or 2). The testing I was reffering to was booting and staying booted into windows... :s



There was no booting at 1.5V with 4 modules. 1 & 2 modules would boot fine and test fine. 3 Modules would boot but memtest would spew errors and prime95 would not go for more than 3 seconds. Upping to the possibly crazy 1.8V (in a different forum I was advised to up a few points :s) cleared the errors on 3 modules.



After more reading...

I have upped to 1.65V and set DRAM speed to 1333 and it appears to all be stable with 4 modules... Running mem test for a few hours, fingers crossed!

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If anything you need to add more memory controller voltage and not buss voltage.


Upping buss voltage from 1.5 to 1.65v is for other modules that require that voltage.Not the Vengeance series on 1155 socket. You'll have to refer to your MB manual for BIOS instructions as to exactly which setting is memory controller voltage. It is called many things across different platforms.


When you populate all four slots in your MB it puts more strain on the memory controller and "AUTO" may not be enough to achieve a stable machine. The modules you have should run at 1.5v no matter what. Seeing as they dont , there is an issue elsewhere in your system.


But to rule out the memory go into your BIOS and load set-up defaults and disable USB legacy support ,then enable XMP profile 1,and test all modules one at a time in the first slot. Let us know how you make out.

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If all 4 modules are working at 1.65V 1333MHz then shouldn't I just be happy with that?

No because on that system they should run at 1600mhz on 1.5v. If it takes 1.65v to run stock at 1333mhz then something is not right.

Also why do you disable usb legacy support?

It will cause false positives with memtest if left enabled while testing.

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Thanks for your reply!


I can't seem to find details on how to up the voltage on the memory controller in my manual, would you mind telling me what else might it be called?


On a side note, after 8 hours of prime95 I got FATAL ERROR: Rounding was 0.5, expected less than 0.4 this resulted in the cessation of testing but not in the pc crashing.


Would really appreciate some more advice. :)


Thanks very much!

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Memory controller voltage is VCCIO in your BIOS . Right under DRAM voltage. Highlight it to see what the actual voltage is and just raise it up .2 volts and retest. You may have to add more then that. But thats a safe starting point and you dont want to add more than you need to make it stable.


This may help you some too...



Second link is actually in the first link but has some good information on memory overclocking as well as CPU overclocking. But at least the memory part is relevant to your issue here. Although a different MB, the principles are the same


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  • 5 months later...

Hello again!


So I had some other serious issues going on outside of my pc so left it working at 1.6v and 1333mhz.


Recently I decided to reformat my computer so I though I would see if there was any updates about my board/ram.


There was a bios update so I decided to give that a go. Upon restarting the computer booted with the ram on default settings (1.5v 1333MHz) but then promptly blue screened. Moving up to to 1.6v and it is stable.


If I move up to 1.7v it works with 1600MHz but memtest gives errors... 1.75v and a few minutes of memtest gives no errors.


Leaving everything as is and changing the VCCIO up from 1v to 1.2v makes no difference, even with the ram running at 1.5v and MHz I get crashes.


So does anyone have any suggestions?


Should I just leave the ram working stably at 1333MHz at 1.6v?


Is it silly to have it running at 1600MHz at 1.75v? (I am guessing your answers will be yes)


Is there a big difference between 1333MHz and 1600MHz?


I would love some advice on what is the best course of action.



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