What is better on a dual channel system. 8gb of ram in one block, or 16gb of ram in two blocks?

[anone234]

Dual Channel doubles the available bandwidth as opposed to single channel.

However, if your CPU or MB can only talk to one channel at a time, does that make the other two sticks of RAM useless? Or are they utilized as storage space while your CPU is working with the other two?

Looking for an in depth answer to this, preferably not a one liner.

 

[Tradesman1]

In dual channel mode, the MC (memory controller) see all the DRAM as a single 128bit device as opposed to the individual 64 bit device that it is, which theoretically doubles the bandwidth, though in actual practice it can boost performance only up to about 10-15%. So as to your question the 2x8GB would provide faster performance overall, though depending on what you do and how, 2x4GB rather than a single 8GB stick would still provide the boost. It comes down to how much you want/need. I recommend 16GB on new builds if for no other reason, DRAM use by the OS, programs and even games continues to rise.

 

[giantbucket]

there was a test once. shows approx 5% or 7% benefit for dual channel versus single channel (total ram amount being equal, though), but not always, sometimes benefit is only 1%. worth it maybe, but not worth worrying about or even thinking about. ram quantity trumps ram channels.

 

[anone234]

Thank you for the detailed answers guys.

So in an effort to sum up what I've read in this thread and others:

For dual channel:

In the example of 2 Sticks of 8gb vs 4 sticks of 4 gb (for a total of 16gb each) the technically better choice would be 2 sticks of 8gb, for a marginal gain that is not very noticeable in practice.

In the example of 2 sticks of 4gb vs 4 sticks of 4gb (8gb vs 16gb) the better choice is more RAM, and going with 16gb will net you more gain.

Please, feel free to correct me if I'm wrong, just trying to sum it up adequately.

 

[giantbucket]

http://www.gamersnexus.net/guides/1349-ram-how-dual-channel-works-vs-single-channel

but i think that was more about 1x8 vs 2x4, and not 2x8 vs 4x4. i think (and right now my memory is shot) that once you go 2xN, you're on dual channel anyways. i'm at work and my mind of focused on other stuff, but 30sec of downtime gets me here.

 

[Tradesman1]

Thank you for the detailed answers guys.

So in an effort to sum up what I've read in this thread and others:

For dual channel:

In the example of 2 Sticks of 8gb vs 4 sticks of 4 gb (for a total of 16gb each) the technically better choice would be 2 sticks of 8gb, for a marginal gain that is not very noticeable in practice.

In the example of 2 sticks of 4gb vs 4 sticks of 4gb (8gb vs 16gb) the better choice is more RAM, and going with 16gb will net you more gain.

Please, feel free to correct me if I'm wrong, just trying to sum it up adequately.

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Yes 2x4GB for 8 total or 2x8GB for 16 total