Mixing Dual Channel and Single Channel RAM...

bbronzanbbronzan
edited January 2006 in Hardware
I currently have an ASUS K8N-E Deluxe motherboard with 512MB Corsair XMS PC3700 ram (Single Channel).

I want to upgrade my RAM with a 1024GB (2 x 512MB) sticks of Corsair XMS PC3700 (Dual Channel) RAM but I was told that you CANNOT mix single and dual channel RAM? My motherboard has 4 slots for RAM, which can either be 4 Single Channel Sticks, or two pairs of Dual channel. If leave my Single Channel 512MB stick in DIMM1 and put the new dual channel sticks in DIMM2, wouldn't that work?

Just want to know if that's possible because a 1GB stick of my RAM is REALLY expensive compared to a dual channel kit.

Thanks! :)

Comments

  • GargGarg Purveyor of Lincoln Nightmares Icrontian
    edited January 2006
    It would work, but it would be single-channel. If you put those extra two sticks in and your computer doesn't show they've been added, then go into your BIOS and turn off dual-channel (shouldn't be necessary, though).

    I think the extra memory capacity will be more beneficial than the extra memory speed, if you're playing modern games or using high-end programs, that is.
  • GobblesGobbles Ventura California
    edited January 2006
    where you will see a notable difference is if you are a gamer, map load times will decrease. If you play battlefield2, you want as much memory as possible as the game runs better if you have more than a gig of ram.
  • deicistdeicist Manchester, UK
    edited January 2006
    And, just to clear up any confusion, even if you did get a 1GB stick of the same type of RAM you have, it wouldn't run in Dual channel with your current 512MB stick. For dual channel to work you have to have the same type & size of memory populating each channel. You seem to be thinking that the RAM itself is dual channel or single channel, that's not true. All RAM is effectively 'single channel', but when you populate both channels on a board with the same type & size RAM then it runs in Dual channel mode. Hope that helps.
  • RWBRWB Icrontian
    edited January 2006
    The only real difference between Dual Channel Memory and Single Channel, is that the Dual Channel stuff is "rated" to run dual channel at the speeds specified. It's actually the same exact memory, they merely tested it more.
  • ronboronbo Connecticut
    edited January 2006
    RWB, a quick question for you. "It's actually the same exact memory, they merely tested it more." Does that mean when memory is manufactured it is not a consistent process? They do not know what they have untill they test it, and the better it test the higher the rating it gets?
  • RWBRWB Icrontian
    edited January 2006
    It kinda depends, but yes. I am no hardware expert, but basically becuase of the extremmely small scale these chips(or any chip) runs at, you can't help but create defects in them. So some are able to clock higher than others, and some don't work at all after being made. Of course this is also to explain how some things overclock better than others, so to speak.

    With "Dual Channel Memory" they just take two regular "Single Channel Memory" modules and put them in a testbed and see how well they run at certain speeds TOGETHER.

    So let's say that these two single channel modules were normally rated to run at PC3200 speeds in single channel mode, when you try to run them at PC3200 levels while running in Dual Channel mode they may only run at PC2700 levels... but of course they could possibly run at PC3200 levels still too. Like I said, it's just a test to be sure they do what they should.

    So let's say again.... you buy a Kingston 512MB stick of PC3200 memory. Just regular memory, not rated for Dual Channel. Then a year later you buy another stick of Kingston 512MB PC3200 memory(the same type as before), meanwhile you upgrade your motherboard to one that is capable of Dual Channel. When you put the two sticks in, it CAN run in Dual Channel mode, but perhaps only at PC2700 levels. It really depends on the quality of the memory, timings, etc...

    FYI: I've had two different sticks of memory, from different manufacturers, run in Dual Channel mode without any problems that I can recall. The only similarities of the memory was that they were both PC3200, and both could run CAS2.
  • muddocktormuddocktor
    edited January 2006
    RWB's explanation is pretty well spot-on. All dual channel memory is just tested to run in dual channel mode at it's rated speed and timings. You can also buy the very same sticks separately and have a very good chance they will run like that too, especially if they are from the same batch number. I have 2 sticks of Corsair XMS3200C2 I bought a few years ago at the same time (it was quite a bit cheaper and available as single sticks, but the DC kits were sold out at the time) and they will run in excess of 250 fsb at 2-2-2-8 timings with around 3.3v in dual channel mode. I also have another setup that will run in dual channel mode at a 200 fsb that consists of 1 stick of Kreton 3200 and 1 stick of Corsair Value 3200. They do need 2.9v vdimm to do it though as the Kreton ram is kinda weak at lower volts.
  • TheLostSwedeTheLostSwede Trondheim, Norway Icrontian
    edited January 2006
    Another thing,

    You use a cpu that doesn't support dual channel in the first place so for that particular setup, it doesn't matter if it's dual channel ram. But for a future rig, you should get a dualchannel kit while you are at it for supporting purposes in case the 2 sticks aren't identical. :)
  • RWBRWB Icrontian
    edited January 2006
    MackanzOCZ wrote:
    Another thing,

    You use a cpu that doesn't support dual channel in the first place so for that particular setup, it doesn't matter if it's dual channel ram. But for a future rig, you should get a dualchannel kit while you are at it for supporting purposes in case the 2 sticks aren't identical. :)

    CPU? A CPU may not be capable of taking full gains from Dual Chennl Memory goodness, but I don't see the CPU listed anyways. You mean the Motherboard?
  • deicistdeicist Manchester, UK
    edited January 2006
    RWB wrote:
    CPU? A CPU may not be capable of taking full gains from Dual Chennl Memory goodness, but I don't see the CPU listed anyways. You mean the Motherboard?

    well that motherboard is a socket 754 board, and no socket 754 board can support dual-channel memory because the memory controller (which is actually on the CPU, not the board) only supports single channel RAM.
  • TheLostSwedeTheLostSwede Trondheim, Norway Icrontian
    edited January 2006
    It's the cpu that needs to support dual channel. S754 only have one memory channel. S939 and S940 have 2. Therefore, dualchannel. 2 or 4 sticks of ram is another thing though.
  • RWBRWB Icrontian
    edited January 2006
    MackanzOCZ wrote:
    It's the cpu that needs to support dual channel. S754 only have one memory channel. S939 and S940 have 2. Therefore, dualchannel. 2 or 4 sticks of ram is another thing though.


    Opps forgot the memory controller was on the A64 for a moment :doh:
  • bbronzanbbronzan
    edited January 2006
    Whoa... you guys sure helped me out ALOT! Thanks! lol So I'm going to look into buying the RAM now that I know what to look for. As for the motherboard issue, I realized that I posted the wrong motherboard. The one I have is different and I checked that manual last night and it does run dual channel which is good. But what I might just do is buy a 1 GB stick of my model of RAM and just use 1.5GB single channel. Because I want to upgrade by ATLEAST 1GB and it wouldn't matter if I bought 1 GB dual channel kit or just bought a 1GB stick cuz it will all run at single channel anyways!

    But thanks again for all your help and I'm gonna make my purchase...hehe.

    Cheers :thumbsup:
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