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Ram Placing on Mobo

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September 14, 2010 4:41:17 PM

Hello, I have a question. My mobo supports dual channel. I already have a 2gb stick. Now i have another 3 x 1gb sticks. How do i run them in dual Channel mode? Here is how my slots are on my mobo:

¦¦ ¦¦ ¦¦ ¦¦
¦¦ ¦¦ ¦¦ ¦¦
¦¦ ¦¦ ¦¦ ¦¦
¦¦ ¦¦ ¦¦ ¦¦
¦¦ ¦¦ ¦¦ ¦¦
A1 B1 A1 B1

So where do i put my 2gb stick and where do i put the rest?
My Mobo is an Asus M4a79XTD and the manual doesn't make it very clear. Also all ram sticks run at 1333 mhz and at 1.5V. I hope the latter helps.

Hoping to hear from somone soon.

More about : ram placing mobo

September 14, 2010 5:30:36 PM

Quote:

Besides you cant mix ram unless it's the same voltage and timings as the other ram.

Yes you can. It will just default to the highest timings, just as it defaults to the lowest frequency among the chips. Not so sure what the voltage would default to. Might have to set it manually if it is different.

As zipzoomflyhigh said though, you cannot use all of your memory and keep a dual channel configuration. But in 95% of circumstances you will have better performance with all 5GB in single channel than with 2GB in dual channel. Actually, the performance benefit of dual channel is a bit contested.
September 14, 2010 5:54:26 PM

Quote:
No you cannot run in dual channel mode unless you just use 2 of your 1gb sticks in A1/A1 or B1/B1

Besides you cant mix ram unless it's the same voltage and timings as the other ram.



I thought i mentionned in my OP that all timings, voltage and speed of ALL ram sticks were the same. Sorry if i wasn't clear enough.
I wold like soomeone to ecplin to me why it's impossible to not run in dual channel mode...is it because they are not the same size in terms of gb?
Also If i'm unabale to run memory in Dual Channel mode will it still be possible for me to install all four sticks of ram in my mobo regardless of whether they run in dual channel mode or not?

Thanks again.
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September 14, 2010 5:57:45 PM

Also If i'm unable to run memory in Dual Channel mode will it still be possible for me to install all four sticks of ram in my mobo regardless of whether they run in dual channel mode or not?
September 15, 2010 12:13:59 PM

Quote:
Yes you can install all of them. But you'll take a big performance hit in single channel mode.

Big performance hit? Certainly not. Theoretically yes, but not in practicality. Slight performance hit? perhaps.
September 15, 2010 4:08:24 PM

If i place my 2gb stick in A1 DIMM SLOT and then place two 1gb sticks in DIMM SLOTS B1 and B2, will the the 1 gb sticks be running in DUAL CHANNEL?
September 15, 2010 4:10:25 PM

BTW my original POST is kinda wrong my RAM slots are as follow: A1 B1 A2 B2
September 15, 2010 4:10:50 PM

David Gill said:
If i place my 2gb stick in A1 DIMM SLOT and then place two 1gb sticks in DIMM SLOTS B1 and B2, will the the 1 gb sticks be running in DUAL CHANNEL?

No. We've already told you that there is no way for you to run dual channel.

Actually, I may be wrong, depending on chipset. I found this on wikipedia
"Certain Intel chipsets support different capacity chips in what they call Flex Mode: the capacity that can be matched is run in dual-channel, while the remainder runs in single-channel."
But there is no mention of which chipsets.

So stick two 1GB sticks in one matching coloured slots and stick the 1GB and 2GB in the other two. You never know.

But there is nothing you can do beyond that. Honestly, don't worry about it.
September 15, 2010 4:48:49 PM

ok, this is what i have in my mobo manual. Tell me what you make of it.

You may install varying memory sizes in channel A and B. The system maps the total size of the lower sized channel for the dual channel configuration. Any excess memory from the higer sized channel is then mapped for a single channel operation.

Source: Asus manual for motherboard M4A79XTD-EVO


I guess thats telling me that if i place a 2 gb stick in DIMM slot A1 and a 1 GB stick in B1 then my system will be running in dual channel mode using 1gb from my 2gb stick and 1gb from the 1gb stick. Also the excess memory from the 2gb stick which is 1gb (2gb - 1g = 1gb) will be running in single channel mode.

Anyway now this is goin to be fun, only way to find out is to try it out myself.
September 18, 2010 6:00:13 PM

So just to give you guys an update. :) 

I installed a stick of 2 gb ram and a stick of 1 gb ram in Slots A1 & B1 as specified by the motherboard manual( to run Dual channel mode) and it WORKS! Memory modules are not required to be of the same size in order to run dual channel mode, but it's best to have the same speed, Voltage and timings.
So now in CPU-Z it confirms that i have Dual channel mode enabled and that my sticks of ram are running in UNGANGED mode. Also both are running at rated speed and at 1.5V.
IF you have any other questions just ask...
September 19, 2010 8:40:36 AM

This topic has been closed by Mousemonkey
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