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Lenovo Staff
Views: 3,759

Question

I need to upgrade the RAM in my D20 (4158), with 2 x X5680 Westmere EP Xeons and currently 12 x 8GB RDIMMS installed. The X5680 officially supports up to 288 GB RAM, so could I safely install 12 x 16GB modules? Would it also be possible to mix modules, i.e. 3x16 GB + 3x8 GB per CPU? 

Answer

12 x 16GB RDIMMs will be fine.   Note that mixing 16GB and 8GB modules will work best if you install the 16GB in slots 1/2/3 and 4/5/6 for CPU 1 and 2 respectively, then fill the remaining slots with the 8GB modules.

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Comments
nikey22

This should work but I think there will be a speed penalty for this. according to the hardware installation manual (~page 50) If you choose to install 1 to 3 modules in each CPU bank, bios will do 1066Mhz so the best you could do @ 1066Mhz is to install 3 DIMMs for CPU1 and 3 DIMMs for CPU2 for a max of: 96Gb. If you choose to install 4 to 6 modules in each CPU bank, bios will do 800Mhz maxing out then, 12 modules, brings you up to 192Gb @800Mhz. At the time the manual was written - PC3-8500R was capable of going up to 800Mhz/1066Mhz. If you happen to find a 16Gb module that runs at 1333Mhz, all of the above I just said may not be true! So I'm not sure if the speed is a BIOS/motherboard limitation or simply a module limitation.

 

Could you imagine 192Gb of RAM @ full speed 1333Mhz?