I bought 8GB RAM from ebay. It was supposed to be 4GB + 2 x 2GB sticks. However, when I put in the RAM it only shows me 6GB.

I thought it was only 4GB + 2GB modules working, however CPU-Z shows that all the modules are being used and size of every modules is 2GB.

Did I get wrong item? Is there a possibility that item is actually 4GB of RAM and it just shows wrong results? Or indeed I've been handed 3 sticks of 2GB RAM?

enter image description here

Edit: Case closed! Seller has refunded me 25% of the price I paid for the missing RAM.

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    What does the sticker on each stick say is the size of the module? Sounds like your motherboard only supports 6GB. More information and please be careful of the language you use. Modify your question to address these questions, post screenshots of the exact items in question as a comment, and they will be added to your question for you. – Ramhound Aug 14 '13 at 12:31
  • Also, what does the computer show if you install only the two 2GB sticks? The motherboard make and model might also be helpful. – a CVn Aug 14 '13 at 12:32
  • motherboard is ASUS P6T, I don't believe it would support 6GB MAX – user245584 Aug 14 '13 at 12:38
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    @user245584 To answer that question I would refer to your mobo manual, all mobos are different in that sense and I have never worked with a 6 DIMM board. Generally though, mixing and matching ram like that means you get knocked down to the lowest timing.In this case of three DIMM channels I would imagine your 4GB is being knocked to 2GB to match your 2GB sticks (hence 3 x 2 = 6GB). As an aside you may be able to bypass this by putting your 4GB stick into your second channel ( a black slot) and keeping the 2GB in orange. – Jason Bristol Aug 14 '13 at 12:49
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    Make sure your using the correct number of sticks for the desired memory configuration. If you have 6 slots you have to use a certain configuration to only use 3 sticks. The correct configuration is in the manual. If you can only see 6GB its entirely possible on stick simply isn't working. – Ramhound Aug 14 '13 at 13:31

You have 3 2GB modules.

The part numbers can be found on Google. CMV4GX3M2A1333C9 is a 4GB dual channel kit (two 2GB memory modules).

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    Yes sir! corsair.com/cmv4gx3m2a1333c9.html Great catch – Austin T French Aug 14 '13 at 16:44
  • @AthomSfere ,@x22 iam not sure what does this mean.can you please explain.and is there anything to do with in placing 4gb dual channel kit in bank 0 and the rest in bank 1 ? – Ashildr Aug 14 '13 at 17:16
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    @AswinKV Most motherboards support installing DIMMs in pairs or "dual channels" to improve performance. The CMV4GX3M2A1333C9 in the picture is only one of two 2GB DIMMs which was supposed to be sold as a pair, or "Dual channel kit." – rob Aug 14 '13 at 17:18
  • that feels much better – Ashildr Aug 14 '13 at 17:20

I hope you are using a motherboard which supports Dual-channel architecture.The proper configuration for your motherboard is 2 DIMMs or 4 DIMMs, NOT 3 DIMMs (unless you use a motherboard which supports a triple channel architecture).

For dual channel configuration and best performance DIMMs (dual inline memory module) need to be installed in pairs.

e.g. look at the pic of dual channel memory slot shown below.

enter image description here

The colors indicate which bank they belong to, bank 0 or bank 1, e.g. lets assume orange is bank 0 and yellow is bank 1.

Then one can place a matched pair of memory modules in bank 0, but a different-capacity pair of modules in bank 1, as long as they are of the same speed.

Using this scheme, a pair of 2 GB memory modules in bank 0 and a pair of matched 4 GB modules in bank 1 would be acceptable for dual-channel operation.

Modules rated at different speeds can be run in dual-channel mode, although the motherboard will then run all memory modules at the speed of the slowest module.

suggestion:Don't try to mix and match 3 different types and 3 different sizes of RAM.

you may try

  1. remove each stick and run them independantly to see if you have a bad stick or bad dimm slot

  2. also check if you have 2gb allocated to your onboard video.

  • They will run at the slowest speed, not the smallest capacity. If I mix 1, 2, 4, 8 on a board that supports 8GB per slow I will have 15GB, not some odd cut. This is not RAMBUS... – Austin T French Aug 14 '13 at 16:50

If you have not done so already, try them one at a time. That way you will know the true sizes of each one. If that happens, then Jason is right and the system is assuming the sticks are all the same size; try swapping the sticks around until the system recognizes them correctly.

Also check your documentation to ensure that your board can actually recognize 4GB sticks.

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