Dual Channel RAM, how does that really work?

Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

How does dual channel ram actually work. I know it makes up a 128-bit
channel when you use two dimms placed in the correct locale, but what does
that really mean to the two dimms? Is it similar to RAID for hard drives,
so that if you store, for example, a 1mb exe file into ram as do all
programs, does 512kb get stored to dimm 0, and 512k to dimm 2 (just because
in dual channel, usually dimm0 & 2 make up a chanel, and dimm 1 & 3 do as
well, atleast on a 4-dimm board, like mine).
4 answers Last reply
More about dual channel work
  1. Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

    On Tue, 20 Apr 2004 02:28:23 GMT, "Anonymous Joe" <anonymousjoe@net.net>
    wrote:

    >How does dual channel ram actually work. I know it makes up a 128-bit
    >channel when you use two dimms placed in the correct locale, but what does
    >that really mean to the two dimms? Is it similar to RAID for hard drives,
    >so that if you store, for example, a 1mb exe file into ram as do all
    >programs, does 512kb get stored to dimm 0, and 512k to dimm 2 (just because
    >in dual channel, usually dimm0 & 2 make up a chanel, and dimm 1 & 3 do as
    >well, atleast on a 4-dimm board, like mine).

    If a disk paradigm you must have, think of the pair of dimms as a 2-way stripe
    set...

    hth ;-)

    /daytripper
  2. Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

    In article <s35980d9e6oje8bp85tjkvip3ikhdokrpk@4ax.com>,
    day_trippr@REMOVEyahoo.com says...
    > On Tue, 20 Apr 2004 02:28:23 GMT, "Anonymous Joe" <anonymousjoe@net.net>
    > wrote:
    >
    > >How does dual channel ram actually work. I know it makes up a 128-bit
    > >channel when you use two dimms placed in the correct locale, but what does
    > >that really mean to the two dimms? Is it similar to RAID for hard drives,
    > >so that if you store, for example, a 1mb exe file into ram as do all
    > >programs, does 512kb get stored to dimm 0, and 512k to dimm 2 (just because
    > >in dual channel, usually dimm0 & 2 make up a chanel, and dimm 1 & 3 do as
    > >well, atleast on a 4-dimm board, like mine).
    >
    > If a disk paradigm you must have, think of the pair of dimms as a 2-way stripe
    > set...

    With a 16-byte stripe?

    --
    Keith
  3. Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

    On Fri, 23 Apr 2004 21:40:22 -0400, KR Williams <krw@att.biz> wrote:

    >In article <s35980d9e6oje8bp85tjkvip3ikhdokrpk@4ax.com>,
    >day_trippr@REMOVEyahoo.com says...
    >> On Tue, 20 Apr 2004 02:28:23 GMT, "Anonymous Joe" <anonymousjoe@net.net>
    >> wrote:
    >>
    >> >How does dual channel ram actually work. I know it makes up a 128-bit
    >> >channel when you use two dimms placed in the correct locale, but what does
    >> >that really mean to the two dimms? Is it similar to RAID for hard drives,
    >> >so that if you store, for example, a 1mb exe file into ram as do all
    >> >programs, does 512kb get stored to dimm 0, and 512k to dimm 2 (just because
    >> >in dual channel, usually dimm0 & 2 make up a chanel, and dimm 1 & 3 do as
    >> >well, atleast on a 4-dimm board, like mine).
    >>
    >> If a disk paradigm you must have, think of the pair of dimms as a 2-way stripe
    >> set...
    >
    >With a 16-byte stripe?

    That'd depend on the burst length (which is usually figured based on cache
    line size) so a cache line of 32 bytes with a "dual channel" memory, a 16 byte
    stripe would be correct...

    /daytripper
  4. Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

    In article <rjrl80hv1hbvrqp8k6vgfdd6lt4bb8tbuf@4ax.com>,
    day_trippr@REMOVEyahoo.com says...
    > On Fri, 23 Apr 2004 21:40:22 -0400, KR Williams <krw@att.biz> wrote:
    >
    > >In article <s35980d9e6oje8bp85tjkvip3ikhdokrpk@4ax.com>,
    > >day_trippr@REMOVEyahoo.com says...
    > >> On Tue, 20 Apr 2004 02:28:23 GMT, "Anonymous Joe" <anonymousjoe@net.net>
    > >> wrote:
    > >>
    > >> >How does dual channel ram actually work. I know it makes up a 128-bit
    > >> >channel when you use two dimms placed in the correct locale, but what does
    > >> >that really mean to the two dimms? Is it similar to RAID for hard drives,
    > >> >so that if you store, for example, a 1mb exe file into ram as do all
    > >> >programs, does 512kb get stored to dimm 0, and 512k to dimm 2 (just because
    > >> >in dual channel, usually dimm0 & 2 make up a chanel, and dimm 1 & 3 do as
    > >> >well, atleast on a 4-dimm board, like mine).
    > >>
    > >> If a disk paradigm you must have, think of the pair of dimms as a 2-way stripe
    > >> set...
    > >
    > >With a 16-byte stripe?
    >
    > That'd depend on the burst length (which is usually figured based on cache
    > line size) so a cache line of 32 bytes with a "dual channel" memory, a 16 byte
    > stripe would be correct...

    Actually I forgot the --> ;-)

    --
    Keith
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