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ATorr37
Beginner
93 Views

Upgrading RAM on DX79SR mobo, what combos work?

I have a DX79SR mobo that currently has 4 sticks of 4GB DDR3-1600 installed. I want to upgrade to at least 32GB, but want advice as to the best approach.

Can I mix 4 and 8 GB sticks?

If I get faster memory will the system use the higher speed or will it be limited to the current speed?

The documentation I have isn't at all clear about combining different sizes / speeds and what will work.

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4 Replies
AlHill
Super User
49 Views

ATorr37
Beginner
49 Views

Thank you for the link, but it really doesn't answer my questions - I had found it earlier and it doesn't indicate if I can combine different size / speed sticks or not, and what results I can expect if I do... I know the board has 4 channels with two sockets per channel. I assume that I need to have matching sticks in each channel, but can I do something like fast 8GB sticks in channels 1 & 2 and 4GB sticks in channels 3 & 4?

 

n_scott_pearson
Super User Retired Employee
49 Views

  • You can use DIMMs with differing device densities, but the density of a DIMM cannot exceed 4Gb (that's small 'b' for gigabit). This means that single-sided 8GB (that's big 'B' for gigabyte) DIMMs cannot be used (they would necessarily use 8Gb density).
  • All DIMMs should have x8 organization. You cannot use double-sided DIMMs with x16 organization.
  • You can mix speeds, but the speed of the slowest DIMM installed will be used for *all* DIMMs installed. There is no advantage to purchasing faster DIMMs of you want to use the DIMMs you currently have. You should match speeds when putting two DIMMs in a (single) channel. You cannot use double-sided 2400MHz DIMMs.
  • You can mix sizes, but if you have two DIMMs in a single channel, they should be the same size. For example, you could take the four 4GB DIMMs you have now and put them into two of the channels and then put one 8GB DIMM in each of the other two channels and reach a total of 32GB.

 

...S

ATorr37
Beginner
49 Views

Thank you VERY much Scott, that is a very helpful and complete answer - tells me just what I need to shop for!

ex-Gooserider

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