3 Replies Latest reply on Apr 18, 2013 11:08 AM by ECBowen

    Mismatched / Uneven RAM


      I currently have 4x4GB of RAM, and I bought a new set of 2x8GB. Will performance be worse when using 2x4GB and 2x8GB since it is not all the same (totaling 24gb vs my previous 16GB)?

        • 1. Re: Mismatched / Uneven RAM
          Harm Millaard Level 7

          Since you are talking about 6 sticks, I presume you have a X59 platform, correct?


          In that case, make sure you have three identical sticks in each bank, for instance 3 x 4 GB and 3 x 8 GB (if 8 GB sticks are supported, which is rarely the case). Do not mix different sticks in one memory bank.

          • 2. Re: Mismatched / Uneven RAM
            RjL190365 Level 4

            Actually, the OP is going to leave out two of the 4GB sticks. Therefore, going with only four sticks total - 2 x 8GB plus 2 x 4GB.


            In this case, the OP must have had either an LGA 1155 build or an LGA 2011 build (the older LGA 1156 platform does not officially support 8GB sticks). In the case of LGA 1155, dual-channel operation is still in effect, depending on which slots the particular sticks are installed in. (In this case, performance in CS6 will be a bit faster with 24GB than with 16GB but not as fast as with 32GB.) But on an LGA 2011 platform, memory controller performance will be degraded: Depending on the BIOS of the LGA 2011 motherboard in question, the memory controller will either default to the Flex memory controller mode (in which 16GB will run in quad-channel and the remaining 8GB will run in single-channel) or entirely to the single-channel mode.

            • 3. Re: Mismatched / Uneven RAM
              ECBowen Most Valuable Participant

              Since 4GB and 8GB have different timings I would not recommend this configuration. That will force the controller in the CPU to moderate the differences and right now and board's do not have the best timing detection to sort that out. The suggestion is to run just the 8GB for now.