Archived from groups: alt.comp.periphs.mainboard.msi-microstar (
More info?)
Phueque <Phueque@evilwork.com> wrote in
news:4bbqu0hoe8b1bmrcpep7cfajpst8tfsdj4@4ax.com:
> How did you check that? From my understanding Dual Channel was a
> special mode that existed only if Slot 1 and Slot 2 had paired memory
> in them. It is kind of like striping a pair of Hard Drives for better
> performance.
BIOS reports "High Performance Dual Channel Mode" during boot.
> The third DIMM can only be accessed at it's normal bandwidth and the
> memory controler wasn't supposed to be smart enough just address that
> RAM more slowly.
Slots 1 & 2 are on channel 1 while slot 3 is on channel 2. If you only
populate slots 1 & 2 (or only slot 3) then you are only using one
channel. If the channels are unbalanced (eg. channel 1 = 128MB & channel
2 = 256MB) the memory controller will only operate in single channel
mode. If, however, you add an additional 128MB to channel 1 in the above
configuration you now have balanced both channels (both have 256MB) and
the memory controller can operate in dual channel mode, potentially
doubling memory bandwidth. On AMD based systems it only makes a
difference if you are using the built in video controller as
Athlon/Duron/Sempron/... are not nearly as bandwidth starved as Intel
processors.
> Did you run any test to prove this?
SANDRA shows about 5-8% performance gain on my systems running dual
channel vs single channel.
>And how do you determine what memory block is accessed?
Huh?
> On Sun, 16 Jan 2005 18:42:26 GMT, "G.M." <bitbucket@cox.net> wrote:
>
>>Phueque <Phueque@evilwork.com> wrote in
>>news:r30lu0tvil17kbettpm19fg0adfgh1g1n7@4ax.com:
>>
>>> Great idea, but no. It won't work.
>>>
>>> The nForce2 MB drops dual channel when the third dimm is installed.
>>>
>>
>>Untrue. Slots 1&2 make up one channel and slot 3 the second. As long
>>as you keep both channels balanced the board will function in dual
>>channel mode. For instance, my setup is as follows: slot1=512MB,
>>slot2=512MB, slot3=1GB. Since both channels are balanced, with 1GB
>>apiece, I can, and do, run in dual channel mode (not that it makes
>>that much difference on an AMD based system)
>>
>><snip>
>
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