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I've got an Asus P5N-EM HDMI motherboard. When I run CPU-Z, it says my Memory is Single Channel. Currently, i have 2x2GIG Kingston DDR2 ram modules installed.

These are the screenies from CPU-Z:

alt text

alt text

Note: Both slot #1 and slot #3 have the same data.

Should I be trying to go dual channel? Should I care?

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@Pure.Krome: Try the RAM in the black slots and see if CPU-Z changes it's information. – JFV Jul 21 '09 at 19:25
up vote 6 down vote accepted

Looking at your board it appears that Slot#1 and Slot#2 (colored black?) should be used for the memory -- this ASUS board has 3 memory slots instead of the usual 4 and they are organized differently. Alternate is not right here.

alt text

A good article discussing Dual-Channel RAM,
Everything You Need to Know About Dual Channel

Dual channel is the ability that some memory controllers have to expand the width of their data busses from 64 to 128 bits. Considering that everything remains the same (clock speeds, for example), the memory maximum theoretical transfer rate is doubled by the use of this technique.

Memories based on DDR (Double Data Rate) technology such as DDR-SDRAM, DDR2-SDRAM and DDR3-SDRAM transfer two data per clock cycle. Because of that they achieve double the transfer rate compared to traditional memories (such as the original SDRAM) running at the same clock rate.

For dual-channel technology to work you need to have an even number of memory modules on your system (assuming that your AMD CPU or Intel chipset support this technology, of course). If you install just one module this technique won’t work because memory will still be accessed 64 bits per cycle. In other words, dual channel works by accessing two memory modules in parallel, i.e. at the same time. Because the two modules are accessed at the same time, they must be identical (same capacity, same timings and same clock rate).

Finally, this is described with more words in the article,
If you have a motherboard with 4 slots, and you own two similar memory sticks compatible with your board, it is critical to place them on the correct two slots (usually alternate slots). The board is wired to use them in dual-channel mode correctly on these placements. Suitable slot pairs are usually colored the same to remind you about this.

So, YES, you should care. You have the right memory (DDR two matched units) and you are running single more just because of incorrect memory placement.

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I'm pretty sure i've now swapped em into slot #1 and slot #2 and it's still saying single-channel :( – Pure.Krome Aug 20 '09 at 1:32
Slot #1 is yellow, #2 is black. The modules should be in slot #1 and #2. However, you are still limited to a single channel as the board only supports one channel. – David Schwartz Feb 4 '13 at 4:01

your mobo supports only single channel mode. usually support for dual channel mode DIMM is not implied but clearly stated. the link you provided mentions single channel DDR2 1066 single channel model only

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No it doesn't matter much at all.

You gain 2% in performance?,1705-11.html

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Dual-channel gives you double the channels for your RAM to do their processing. It makes your RAM even faster, even if it's by a small margin. If I had the choice, I'd go Dual-Channel vs. Single Channel.


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If had the choice? how do i know if i have the choice? – Pure.Krome Jul 21 '09 at 0:03
When you purchase your RAM, it should say on the package (or on the website) that it is dual-channel RAM. Otherwise, the RAM is single-channel (default, or standard RAM). – JFV Jul 21 '09 at 0:14
You can't change single-channel RAM to dual-channel RAM. Dual-Channel RAM is in the way it's designed on the hardware level. – JFV Jul 21 '09 at 0:15
I downvoted your answer because I don't have the ability to downvote your comments. Although RAM can be purchased as "matched pairs," there isn't single-channel or dual-channel RAM. This is all controlled by the memory controller on the motherboard or CPU. More likely than not, the OP does not have the RAM installed in the correct slots, so it is not operating in dual channel mode. – Russ Warren Jul 21 '09 at 16:30

To get RAM to work in dual channel mode, you have to insert it into the correct RAM slots on the motherboard. Please check the manual to see which DIMM slots should be used to use Dual Channel mode.

Each module must be the same size (e.g., 1GB) and preferably the same speed and brand.

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Yep, in this case it's a pair i bought together. I've got the feeling it's a matched pair .. i think. anyways, they are identical (as stated in the opening post). – Pure.Krome Jul 21 '09 at 1:55
Did you put them in the correct DIMM slots? As shown in the other post, you probably have to put them both in the black slots. – Chris Thompson Jul 21 '09 at 3:53
I've done this and it's still running in single mode. – Pure.Krome Aug 20 '09 at 1:31

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