Dual channel RAM not working

Ad Ryan

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Dec 25, 2014
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Hello people of TomsHardware ,

Lately , I have upgraded my rig from 965 be to FX 6300 and also aquired new cooler for it with closed liquid cooling (CM hydro H90). Ever since then my pc doesnt want make my RAMs work in dual channel . What I mean by that ,is that pc is detecting both of RAMs but is only able to use one of them , as whole memmory is reading 4 GB . I have noteced it wheni was putting my old cpu back to factory setting and i saw in bios that pc is using only 4 gigs . I proceeded to swap RAMs and tryied all of possible configurations . The result was that they both work separately , but pc cant read them both in dual channel even is bios is showing both of channels populated . Only once I had success with having it dual channel again , but after cpu and cooler change , I cant seem to make them work again . Same thing happend with another pair of RAMs 2x8 .

So the questions are :

What may be causing this ? As there is no thermal paste leftovers anywhere , no bent pins , also MOBO and PSU are working fine . I am still goin to try to dismount mobo and look properly on pins etc to assure this , but I believe eveyrthing is fine .

They seem to be working when seated in separate slots like a1 b1 setup (not dual channel which is in this case a1 a2) and PC shows both of them active and can access full 8gigs . The question here is : will this affect performance in any ways ? I mean , i know that dual chennel is superrior but will this drop my performance in noticable way ? as for now i find some minor "lags" and pauses in the games i play , can it be happening because of this ? When pc is using 4gb but once it need more that that it have troble reading the other RAM and there is the lag ? Am not sure how this works so please shed some light on it for me :)

Will it also be more viable for me selling those and getting single RAM ?

tl;dr
RAM is not working in dual channel setup as pc is recognizing only half of RAM but both slots are clearly populated in BIOS . They work however in not dual channel setup meaning a1 b1 slots are populated . Same with another pair of rams .

Thank you for any help in advance :)

my spec :

MOBO : ASUS M5a99x EVO (UEFI BIOS)
CPU : AMD FX-6300 @ 4Ghz
GPU : AMD Sapphire radeon HD 7850 OC @ 2GB
RAM : GOODRAM Play 8GB 1333Mhz
HDD : WD 1TB
SSD : Kingston hyper x 120GB
PSU : 600 W


 

Neur0nauT

Admirable


Thats a strange one. You mentioned that the RAM modules are both working when in separate channel slots to give the full 8GB? It sounds like one or more slots maybe faulty then. You might have to consider RMA'ing your motherboard under warranty.

 

Ad Ryan

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Dec 25, 2014
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Well , MOBO is not under warranty anymore , so this option is not possible . I have few things i want to try beffore calling it failure , but when it will happend , what is the best step for me here . Sticking with those cards being in separate slots or selling them and getting one single slot ?
 

Neur0nauT

Admirable


On separate slots the memory bandwidth will be reduced, but it should be unnoticeable, at least you will have all available RAM.

I found an older post of a guy with the same issue. See if any of these suggestions are helpful: http://www.tomshardware.co.uk/answers/id-1715959/dual-channel-memory-issues-16gb-installed-8gb-detected.html

 

holyprof

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Dec 16, 2011
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As Neur0nauT mentioned, it seems to be a problem with the "a2" slot. Did you try b1 + b2 combination? Some motherboards allow it and it works just as well as a1 + a2 setup.
Losing dual channel memory is only noticeable in RAM bandwidth limited scenarios, and even then it's not big deal so if nothing else works, use the a1 b1 setup.
 

Ad Ryan

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I will reinstal my win today and i also want to try to reseat the cpu with the RAMs aswell to make sure nothing is damaged physicaly .
So if nothing would work , having my rams in non dual channel config will not degrade their power or ability to perform as good as single 8gb card would ?
 

ThomasLeong

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May 27, 2013
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My guess is bent pins on the motherboard's cpu socket. I experienced a similar scenario myself, and inadvertently bent some of those pins - the section handling memory. Carefully straightening them out solved the problem. Need small-sized screwdriver, credit cards to line up, etc. Youtube has videos on the process.
 

Ad Ryan

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I've also red about case where guy had micrscopic amount of thermal paste on pin which made the same issue . Ill try to reseat and check cpu properly of anything is damaged . Should this damage u mentioned be visible ?
 

ThomasLeong

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May 27, 2013
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Yes, should be clearly visible on the motherboard's socket for the cpu (I'm assuming AMD is similarly designed to Intel; not familiar with AMD). Those on the mobo socket are made of copper, very, very easily bent. In good condition, they should all be symmetrical vertically and horizontally - easy to see this symmetrical arrangement.
 

Ad Ryan

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You can check the images of my MOBO on google . This socket especialy has sort of hidden pins i would say .I am not home atm so i cant confirm how they look when i check them closely , but its nothing like intels sockets which has pin right on the open not covered by any plastic . Should the pins still be visible and eligible to be bent back to its place ?
 

ThomasLeong

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May 27, 2013
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No way for me to see the socket up close via the web. Pix are all too small to see details. You are in the best position, as an owner, to see the real thing up close.

I really doubt AMD cpus are that different in design to Intel's. For Intel these days, the cpu side has the contact points, not pins. The pins are on the motherboard socket, and in the box are protected by a piece of plastic which one has to remove, carefully, in order to 'install' the cpu onto it, then lock it down.