<matt.j.ev...@NOSPAMbtinternet.com> wrote: >I have 2 x 256 2700 sticks and 1 x 512 2700 sticks. >Slots 1 & 3: 256 >Slot 2: 512 >or >Slot 1: 512 >Slots 2 & 3: 256? >I have gone for the former. I'm guessing it will utilise dual ddr better to >have 2 of the same memory in 1 & 3. Am I right?
No. You must have equal amounts of memory in each channel so go for the latter.
My goodness...this issue just seems to cause so much hand-wringing. (And I'm not being critical, because my hands get wrung too!)
When I built this system, I put a pair of 256's in 1 & 3 too. Then last week I added a 512 in between. AFAIK it's fine. And by "fine" I mean the whole 1024 is running in d/c. But then somebody comes along and says no, and...well...I start wringing again.
I guess I'm still a bit unclear on the whole bank/bus/slot/channel relationship. Ben has patiently explained it over and over, but for some reason I find it difficult to comprehend.
Perhaps someone could re-phrase the explanation. (Naturally we'd like to install the sticks in the best possible config!) Meanwhile, it's comforting to see that I'm not the only one!
> My goodness...this issue just seems to cause so much hand-wringing. (And > I'm not being critical, because my hands get wrung too!)
> When I built this system, I put a pair of 256's in 1 & 3 too. Then last > week I added a 512 in between. AFAIK it's fine. And by "fine" I mean the > whole 1024 is running in d/c. But then somebody comes along and says no, > and...well...I start wringing again.
> I guess I'm still a bit unclear on the whole bank/bus/slot/channel > relationship. Ben has patiently explained it over and over, but for some > reason I find it difficult to comprehend.
> Perhaps someone could re-phrase the explanation. (Naturally we'd like to > install the sticks in the best possible config!) Meanwhile, it's comforting > to see that I'm not the only one!
> Regards, > Ron
Well I look at it this way. If I only had 2 x 256 I would use slots 1 and 3 (as per the manual and everything else you read about dual ddr). Seeing as I only have 3 slots it seems logical that the 512 would go in the middle.
<matt.j.ev...@NOSPAMbtinternet.com> wrote: > "Ron" <pls-reply2gr...@urleisure.ca> wrote in message > news:KnSqb.4917$G1.23184@tor-nn1.netcom.ca... > > My goodness...this issue just seems to cause so much hand-wringing. (And > > I'm not being critical, because my hands get wrung too!)
> > When I built this system, I put a pair of 256's in 1 & 3 too. Then last > > week I added a 512 in between. AFAIK it's fine. And by "fine" I mean the > > whole 1024 is running in d/c. But then somebody comes along and says no, > > and...well...I start wringing again.
> > I guess I'm still a bit unclear on the whole bank/bus/slot/channel > > relationship. Ben has patiently explained it over and over, but for some > > reason I find it difficult to comprehend.
> > Perhaps someone could re-phrase the explanation. (Naturally we'd like to > > install the sticks in the best possible config!) Meanwhile, it's > comforting > > to see that I'm not the only one!
> > Regards, > > Ron
> Well I look at it this way. If I only had 2 x 256 I would use slots 1 and 3 > (as per the manual and everything else you read about dual ddr). Seeing as I > only have 3 slots it seems logical that the 512 would go in the middle.
> Someone please tell me if I'm right or wrong.
You should be thinking of it in terms of what the memory has to do. The memory controller alternates between two stacks of memory bytes. It is like the memory is 128 bits wide, instead of 64, so two stacks ("channels") are used. The processor is only 64 bits wide, so it gets data from one stack and then the other. Doing this doubles the rate that the memory can deliver data, as each stack can be working on the problem at the same time.
With 2 x 256MB, you put one stick on each channel -
------- ------- ^ | 256MB | | 256MB | | equal height in each stack of bytes ------- ------- v
When you add 512MB, you need to rebalance the heights of the stacks. If you placed the 512MB in the middle slot, I think that would be 256MB in one stack and 768MB in the other stack. That configuration cannot go back and forth properly, once you get past the initial matched 256MB on each stack.
Placing the 2 x 256 on one channel, and the 512 on the other, means "dual channeling" can be used for all the memory.
------- ------- ^ | 256MB | | | | ------- | 512MB | | equal height in each stack of bytes ------- | Stick | | | 256MB | | | | ------- ------- v
Not that this is that important. On the Nforce2, it seems other optimizations mean that the dual channel thing doesn't give that much of an additional performance boost. So the difference between a misconfigured and a properly configured system is too small to care about.
I tend to agree with Paul, I just went through this yesterday. Had 2x256 and added a 512 in slot 3. Works dual channel fine. 512 also works dual channel in slot one, but I do not think it will be a balanced system in slot 2, I need to try this and se if dual channel comes up after post!
The revised owners manual page about memory at the Asus web site implies that you can install memory in any config and mix but for dual channel you must install in 1 & 3 or 2 & 3 for 2 sticks and 1,2,3 for 3 sticks.
I have another machine that I am testing 3 sticks of 256 in and the bios says dual channel and memtest86 is indicating the correct speed. I have to assume the bios knows and that the upper 256 meg is not running in single channel mode.
In other words it seems that the amount of memory doesn't matter for dual channel as long as you install in 1 & 3 or 2 & 3 for 2 sticks and 1,2,3 for 3 sticks. BTW, my 3 stick machine with 3 256 meg modules says RAM is in ROWS 0,2,4.
> In article <3fabf6b8$0$261$cc9e4...@news.dial.pipex.com>, "Matt" > <matt.j.ev...@NOSPAMbtinternet.com> wrote:
>> "Ron" <pls-reply2gr...@urleisure.ca> wrote in message >> news:KnSqb.4917$G1.23184@tor-nn1.netcom.ca... >> > My goodness...this issue just seems to cause so much hand-wringing. >> > (And I'm not being critical, because my hands get wrung too!)
>> > When I built this system, I put a pair of 256's in 1 & 3 too. Then >> > last week I added a 512 in between. AFAIK it's fine. And by >> > "fine" I mean the whole 1024 is running in d/c. But then somebody >> > comes along and says no, and...well...I start wringing again.
>> > I guess I'm still a bit unclear on the whole bank/bus/slot/channel >> > relationship. Ben has patiently explained it over and over, but >> > for some reason I find it difficult to comprehend.
>> > Perhaps someone could re-phrase the explanation. (Naturally we'd >> > like to install the sticks in the best possible config!) >> > Meanwhile, it's >> comforting >> > to see that I'm not the only one!
>> > Regards, >> > Ron
>> Well I look at it this way. If I only had 2 x 256 I would use slots 1 >> and 3 (as per the manual and everything else you read about dual >> ddr). Seeing as I only have 3 slots it seems logical that the 512 >> would go in the middle.
>> Someone please tell me if I'm right or wrong.
> You should be thinking of it in terms of what the memory has to do. > The memory controller alternates between two stacks of memory bytes. > It is like the memory is 128 bits wide, instead of 64, so two stacks > ("channels") are used. The processor is only 64 bits wide, so it > gets data from one stack and then the other. Doing this doubles the > rate that the memory can deliver data, as each stack can be working > on the problem at the same time.
> With 2 x 256MB, you put one stick on each channel -
> ------- ------- ^ > | 256MB | | 256MB | | equal height in each stack of bytes > ------- ------- v
> When you add 512MB, you need to rebalance the heights of the stacks. > If you placed the 512MB in the middle slot, I think that would be > 256MB in one stack and 768MB in the other stack. That configuration > cannot go back and forth properly, once you get past the initial > matched 256MB on each stack.
> Placing the 2 x 256 on one channel, and the 512 on the other, > means "dual channeling" can be used for all the memory.
> Not that this is that important. On the Nforce2, it seems other > optimizations mean that the dual channel thing doesn't give that > much of an additional performance boost. So the difference between > a misconfigured and a properly configured system is too small to > care about.
> HTH, > Paul
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> I tend to agree with Paul, I just went through this yesterday. Had 2x256 > and added a 512 in slot 3. Works dual channel fine. 512 also works dual > channel in slot one, but I do not think it will be a balanced system in > slot 2, I need to try this and se if dual channel comes up after post!
Matt wrote: > I have 2 x 256 2700 sticks and 1 x 512 2700 sticks.
> Quick question:
> Slots 1 & 3: 256 > Slot 2: 512
> or
> Slot 1: 512 > Slots 2 & 3: 256?
> I have gone for the former. I'm guessing it will utilise dual ddr > better to have 2 of the same memory in 1 & 3.
> Am I right?
> Matt
OK guys... here I go! :-)
Neither of those two configurations are what I would call "ideal".
The 512MB DIMM should go in slot 3, as slot 3 comprises the second bank, each bank is connected to its own channel. The two 256MB DIMMs should go in slots 1 and 2, 'cos they form the first bank. In this configuration, each bank has 512MB and is thus "balanced" in terms of memory capacity for each channel.
So in short: Dual Channel = Two seperate memory channels. Memory channel 1 is connected to bank 0, which consists of DIMM slots 1 and 2 (the two closest to the CPU). Memory channel 2 is connected to bank 1, which consists of DIMM slot 3.
Personally I would "balance" the memory in each channel.
However, the nForce2 *does not require* equal capacities, timings, speeds, manufacturer, model number or anything else in order to function in Dual Channel mode... it merely requires some RAM connected to each channel.
I don't know how to make it any simpler... :-P
Ben -- I'm not just a number. To many, I'm known as a String...
>Matt wrote: >> I have 2 x 256 2700 sticks and 1 x 512 2700 sticks.
>> Quick question:
>> Slots 1 & 3: 256 >> Slot 2: 512
>> or
>> Slot 1: 512 >> Slots 2 & 3: 256?
>> I have gone for the former. I'm guessing it will utilise dual ddr >> better to have 2 of the same memory in 1 & 3.
>> Am I right?
>> Matt
>OK guys... here I go! :-)
>Neither of those two configurations are what I would call "ideal".
>The 512MB DIMM should go in slot 3, as slot 3 comprises the second bank, >each bank is connected to its own channel. The two 256MB DIMMs should go in >slots 1 and 2, 'cos they form the first bank. In this configuration, each >bank has 512MB and is thus "balanced" in terms of memory capacity for each >channel.
>So in short: >Dual Channel = Two seperate memory channels. >Memory channel 1 is connected to bank 0, which consists of DIMM slots 1 and >2 (the two closest to the CPU). >Memory channel 2 is connected to bank 1, which consists of DIMM slot 3.
>Personally I would "balance" the memory in each channel.
>However, the nForce2 *does not require* equal capacities, timings, speeds, >manufacturer, model number or anything else in order to function in Dual >Channel mode... it merely requires some RAM connected to each channel.
>I don't know how to make it any simpler... :-P
>Ben
So then, if I'm about to buy memory and unsure about 512 or 1g, then I buy two 256 and put them in 2 and 3. And if I buy a 512 later, that goes in 3 and the two 256s move to 1 and 2. That sounds like a plan. Probably better if the 512 is exactly the same type as the 256s but apparently not a requirement. Thanks Ben. 512 for now and maybe another 512 if I ever need it.
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