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Precision 490 Memory RAM rank question: 2rx8, 4rx4 + mixing

Dear community,

I would like to max out the memory on my Dell precision by set of fours (8x4GB= 32gb or 4x4GB = 16GB and later upgrade to 32GB). The User manual says I have to match size, rank and organization of 2 or 4 modules. And of course FB-Dimm (currently 4x 1GB 2Rx8 are installed).

So far, no problem.

However, there are 4GB dual rank and quad rank modules around with different organizations, e.g.

- 2Rx8

- 4Rx4

- 2Rx4

I have read that the total number of ranks is limited by chipset/motherboard/CPU.

When I want to max out the memory per set of four (4x4GB =16GB and later another 4x4GB = 32GB), do I have to go with 2R modules? Or can I also use 4R modules? Or could I also mix them (e.g. 4x 4GB 4Rx4 and 4x 4GB 2Rx8)?

kind Regards,


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Community Manager
Community Manager

RE: Precision 490 Memory RAM rank question: 2rx8, 4rx4 + mixing

Hi chaosprevails,

Thanks for posting.

The Precision 490 can handle up to 32GB of memory in 8 dual in-line memory modules. The 8 memory sockets are split into two sets of four, one for each processor. Each set of four sockets are divided into two channels with two memory slots per channel.

The supported memory DIMM type and size is dependent on your current computer configuration.
The Dell Precison 490 uses 2GB, 4GB, 8GB, or 16GB RDIMMs.
For best performance, fully buffered DIMMs should be installed in sets of four.
Memory frequency is determined by the speed of the DIMMs, speed supported by the processor, and the configuration of the DIMMs.
DIMMs must be installed starting with the slot furthest from the processor.
Always think long term when upgrading memory.

You can purchase RAM from Dell Spare Parts, or for guaranteed retunable parts try Crucial: http://dell.to/2lkOtuS

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6 Thallium

RE: Precision 490 Memory RAM rank question: 2rx8, 4rx4 + mixing

You cannot mix ranks. And Quad Rank HIGH DENSITY Ram is not supported.

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