4 Replies Latest reply on Apr 21, 2009 10:51 AM by STe@lTh

    Intel Xeon 5500 series

    STe@lTh

      Why so degrades memory frequency from 1333MHz to 800MHz when install all memory dimms in the server which based on Xeon5500?

        • 1. Re: Intel Xeon 5500 series
          Christopher Peters

          What specific processor are you using .. processor number or CPU speed or other data would help.

           

          the lower priced Xeon 5500's will only run up to a certain memory speed (see below).  If you have use memory that is capable of running faster it will only run a the the max speed indicated below.

           

          the Xeon E5502, E5504, E5506 will run a max memory speed of 800MHz

          the Xeon E5520, E5530, E5540 will run a max memory speed of 1066MHz

          the Xeon X5550, X5560, X5560 will run a max memory speed of 1333MHz.

           

          Chris

          • 2. Re: Intel Xeon 5500 series
            STe@lTh

            Hi, Chris

             

            Here is of DDR3 memory population guidelines for the HP DL380G6 and for HP DL360 G6 (this information is in the HP Product Bulletin). Even if i wil use the Xeon X5550, X5560, X5560 and install all memory dimms in all slots, dimms speed will be 800Mhz. A similar situation on IBM's servers (x3650 M2, x3550 M2). This is vendors limitations or so works memory controller in the Xeon 5500?

             

            DIMM Type ->Registered  Dimms (RDIMMs)Unbuffered  with ECC DIMMs (UDIMMs)
            DIMM Rank ->Dual  Rank (2R)Quad  Rank (4R)Single  Rank (1R)Dual  Rank (2R)
            DIMM  Capacity ->2GB4GB8GB2GB4GB8GB1GB2GB1GB2GB
            DIMM Native Speed (MHz)  ->133313331067*1067*1333**1333
            SLOTS THAT  CAN BE POPULATED
            18 slot servers181818*12*12**12
            MAXIMUM CAPACITY  (GB)
            18 slot  servers3672144*48*12**24
            POPULATED DIMM  SPEED (MHz)
            1  DIMM Per Channel133313331067*1067*1333**1333
            2 DIMM Per Channel106710671067*800*1067**1067
            3 DIMM Per Channel800800800*******
            *  - not supported by HP at this time.

            NOTES:

            • Mixing DIMM speeds is allowed, but the system processor  speed rules always override the DIMM capabilities
            • If you do mix DIMM speeds,  the memory bus will default to the minimum clock rate of all DIMMs in the system  - even if the slower DIMM is on the other processor
            • If you install 1x  1066MHz DIMM in channel 1 and 1x 1333MHz DIMM in channel 2, you still run at 1066MHz
            • If you install 1x 1066MHz DIMM in channel 1 and 5x 1333MHz DIMMs with 1 DIMM Per  Channel (DPC) in each of the other channels, you run at 1066MHz
            • If  you install 3DPC in one channel (if applicable) and 1DPC in all other channels,  you run at 800MHz
            • 95 Watt CPU's are required for 1333MHz DIMM speeds.  All other CPU's are capable of up to 1067MHz
            • References to the above MHz  speeds are for the various speeds of DDR3 DIMMs; 1333 refers to DDR3-1333, etc.
            • 3. Re: Intel Xeon 5500 series
              Christopher Peters

              You are right .. i forgot about that dependency when i wrote my previous response on why your memory may be running at a slower speed.  the memory speed is also dependent on the number of DIMMs you populate per channel.

               

              one DIMM per channel (up to 6 DIMMs / server)            .. can run 800, 1066 or 1333MHz memory

              two DIMMs per channel (up to 12 DIMMs / server)         .. can run 800 or 1066MHz memory

              three DIMMs per channel (up to 18 DIMMs / server)      .. can run 800MHz memory only

               

              the Xeon E5502, E5504, E5506 will run  800MHz memory speed only

              the Xeon E5520, E5530, E5540 will run 800MHz or 1066MHz memory speed

              the Xeon X5550, X5560, X5560 will run 800MHz, 1066MHz or 1333MHz memory speed.

               

              One other dependency I should note while we are on this topic. If memory reliability features like mirroring or lockstep operation only function if you have 2 channels of memory populated (can't do odd numbers of channels here)

               

              This is a complex topics and we had many questions like yours as we enabled this product across the industry.  Hope this helps ... I have provided a simple visual cheat sheet that i refer to on this topic

               

              chris

              • 4. Re: Intel Xeon 5500 series
                STe@lTh

                Thank you Chris