Dual channel with 3 x 1 GB

Hi,
I'm currently have my RAM in dual channel. In my system right now I have 2 GB of RAM (2 x 1 GB). My friend upgraded his RAM and he's given me his old stick of 1 GB RAM (bringing me to a total of 3 GB of RAM). My RAM and his RAM are not the same brand/company, but are identical in type: they are both DDR2 800.

When I installed the third stick of RAM, CPU-Z is actually reading it in dual channel and it recognizes that I have 3 GB of memory. My understanding is that getting dual channel with 3 sticks is possible (ie having 2 x 1 GB and 1 x 2GB with a total of 4 GB). However I'm not aware that it's possible to achieve dual channel with 3 sticks of the the same size.

Could it be that CPU-Z is reading it wrong? Say that it is, would it be better if I ran the 2 GB in dual channel than having 3 GB not in dual channel? In other words, should I not install my friend's stick of RAM (which is a different brand and has slightly different timings) and just stick to my 2 originals? Thanks.

My parts:
Current Memory: G.SKILL 2GB DDR2 800 http://www.newegg.com/Product/Product.aspx?Item=N82E16820231098

Friend's Memory: Crucial Ballistix DDR2-800 http://www.pricebat.ca/Crucial-Ballistix-PC2-6400-1GB-DDR2-800-CL4-4-4-12-240PIN-DIMM-Memory-Module.p_130331/

MB: P35-DS3L http://www.newegg.com/Product/Product.aspx?Item=N82E16813128059
5 answers Last reply
More about dual channel
  1. The difference between single and dual channel isn't massive I believe,
    about 5% if Toms posters are right.
    I'd stick with the 3Gb and see if you can tighten your timings
    but afaik you cant have dual channel with three sticks of ram, once you add that one in the other channel it goes back to single channel, add another to fill all four slots you get dual again :)
    Moto
  2. Thanks for the reply.

    Well, I am running on WinXP 32 bit. Since the max memory that WinXP 32 can recognize is 3 GB, I'm wondering if that's throwing off CPU-Z in reading that I have a dual channel set up.

    I'm still quite the novice when it comes to overclocking, especially with RAM. In my original two sticks set up, my timings were 5-5-5-15 with a 1:1 ratio (I OC'd my E6750 from 2.6 to 3.2). When I added the third stick, my timing went to 5-5-5-18 while maintaining the 1:1 ratio. What timing would you recommend I try to achieve if I stick with the three sticks?
  3. Nah, I have 4Gb on 32bit Xp as a backup O/s, it can see the 4Gb, but usable is just over 3.2ish
    Although favourable, 1:1 Ratio isn't an absolute requirement, My ram runs at 3:10 fine.
    5-5-5-18 is quite fast timings,you could let those up a bit imo if needed but if your stable, I'd not mess with them tbh
    as for exact ram timings, I'm afraid you'll have to wait for a brainer person to post, I'm not good with Ram timings and wouldn't want to give anyone bad advice. :)
    Sorry I cant be more help man,
    Moto
  4. vwj said:
    Thanks for the reply.

    Well, I am running on WinXP 32 bit. Since the max memory that WinXP 32 can recognize is 3 GB, I'm wondering if that's throwing off CPU-Z in reading that I have a dual channel set up.

    I'm still quite the novice when it comes to overclocking, especially with RAM. In my original two sticks set up, my timings were 5-5-5-15 with a 1:1 ratio (I OC'd my E6750 from 2.6 to 3.2). When I added the third stick, my timing went to 5-5-5-18 while maintaining the 1:1 ratio. What timing would you recommend I try to achieve if I stick with the three sticks?



    Leave the timing set to AUTO... In a scenario of two different brands, the slowest timing set will rule. It won't hurt you're faster modules to run them a little slower, but if you try to speed up the slower module to match timing with the faster set, you're asking for trouble.

    It's like driving on a one lane highway, the care in front sets the speed limit and there's no room to pass.
  5. Yes, I do vaguely remember reading somewhere that the slowest timing will dictate the rest of the RAM. However, I supposedly have somewhat performance RAM and even at that, I should leave the timing to auto?
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