# Bizzare Problem with RAM detection on asus motherboard



## Nevis (Mar 3, 2011)

I'm not sure should I post this on Ram or motherboard thread but I'm sure admin will take care of that if this is posted in wrong place. Anyway to the problem.
I'm having bit of a bizarre problem with bios not detecting all my ram.
The mother board has 4 ram slots so from left to right it should be something like this.
black, light blue, space, black and light blue. 
By the manual than came with the motherboard those slots are named as following:
Black = A2
Light blue = A1
Space
Black = B2
Light blue = B1 (From left to right.)
So I had 2 x 2 gigs ram installed (APACER DDR3-1333 2G DIMM CL9 128*8 ROHS)
In slots A1 and B1. Note these ram sticks are universal not dual channel. So they should work which ever slot I put them right? Well bios detects only 2 gigs.
At first I thought it was just something wrong with the ram. So I bought pair new ones. 
Buffalo 4GB KIT DDR3 1333 RETAIL which is 2 x 2gig dual channel. 
I tried put these in A1 and B1 slots and bios still only detected 2 gigs as ram.
Then I decided to go bit crazy on these sticks and put them all in. I left dual channels as they are and added APACER's sticks in the mix.
So it looks like this:
A2 = apacer 2 gigs
A1 = buffalo 2 gigs
B2 = apacer 2 gigs
B1 = buffalo 2 gigs
Now bios detects 4 gigs only but I have no idea which sticks are actually in use...
I know you shouldn't mix dual channel and normal but this was more of a experiment.
I still can't figure out what is to blame though. Is it motherboard, Ram or just bios settings.

I did read than if you are using somekind specific cpu (mine is intel i5-760) the ram has to be put in A1 and B1 slots. This might explain why pc didn't start up atall if I placed buffalo's dual channel sticks in A2 and B2 and left other slots empty.

Anyway my specs are as following:
Mobo: P7H57D-V EVO
GPU: ATI Sapphire 6850
CPU: Interl i5- 760
Operating System: Windows 7 64bit


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## Tyree (May 10, 2009)

Try using one stick at a time and see what the Bios shows. Do the same with the other 3 sticks. It could be the Mobo doesn't like those brands.


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## gcavan (Aug 13, 2009)

FYI: "Dual Channel" is not a type of memory, but a mode of memory access. All memory will run in Dual or Triple channel mode, if the motherboard supports it. If mismatched DIMM's are used, all memory will run at the highest speed which all DIMM's support. Odd sizes will also run in dual (or even triple) channel mode but the system will map the total size of the lower sized channel for dual mode operation. The remaining memory in the higher-sized channel will then run in single channel mode.

A "Dual Channel Memory Kit" is simply a matched pair of DIMM's which are guaranteed (by the manufacturer) to run in dual channel mode.

Now to your problem:

Run your computer with only a single DIMM in one slot. Retest with the same DIMM in each slot. Retest with each DIMM in each slot.


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## Nevis (Mar 3, 2011)

Thx for the advice. I'll give it a try and get back to you if it helped.
Btw little question is this suppose to solve the actual problem or just find the cause what's doing it like say which ram stick is broken? Also is it enoght than I just run the pc with each stick say untill i get to bios or all the way to windows?


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## Wrench97 (May 10, 2008)

Just to the Bios to see if it's recognized, Slot A1 is usually the preferred slot for single stick operation, dual channel is achieved by using the same color slots.


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## Nevis (Mar 3, 2011)

Ok I went through with testing each ram stick in each slot.. oh well half of the slots anyway since seems like the first set of ram slots work fine but the other set doesn't.
So again from left to right 2 slots from left work but the other 2 on right doesn't.
If I try put ram in those 2 non working slots pc won't boot and I get 1 long beep and 2 shorts beeps which means no memory detected.
And these slots worked fine when I got this pc and used them. Though about 3 weeks ago I started getting these BSODs and ended up reinstalling windows thinking that was causing the problem. Guess that's when the slots gave in.

So I assume the motherboard is bust but I still got 3 years warranty on it. Unless anyone can come up with some bios thingy than might cause this?


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## gcavan (Aug 13, 2009)

Time to contact your retailer (or Asus) for an RMA.


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