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Question about ram speeds, dual channel, and max benefit/capacity

By arasarn
Sep 9, 2008
  1. I have a new mobo on the way, it's a;
    XFX GeForce 8200 Motherboard - NVIDIA GeForce 8200, Socket AM2 / AM2+, MicroATX, Audio, Video, DVI, HDMI, PCI Express 2.0, Hyrbid SLI, USB 2.0, eSATA, RAID, CMOS, DebugLED Displayoard

    Going to be running the AMD Athlon 64 X2 5000+ 2.60GHz Black Edition Socket AM2 Processor and the XFX GeForce 8500 GT Ultra Silent Cooling Video Card - 512MB DDR2, SLI Ready, PCI Express 1.0 x16, (Dual Link) DVI, VGA, HDTV

    and it is coming with this ram;
    Crucial 2048MB PC5400 DDR2 667MHz Memory
    Crucial 1024MB PC5400 DDR2 Memory

    URL for the barebones kit is here;
    tigerdirect.ca/applications/searchtools/item-details.asp?EdpNo=3978475&cm_mmc=Email-_-WebletMain-_-CANLET-_-99order&SRCCODE=CANLET


    Now I know these won't run dual channel but I have a pair of 800mhz corsair high performance 1gb sticks that are designed to run dual channel.

    ncix.com/products/index.php?sku=18580&vpn=TWIN2X2048%2D6400C4&manufacture=CORSAIR&promoid=1043

    (Corsair XMS2 TWIN2X2048-6400C4 2GB 2X1GB PC2-6400 DDR2-800 CL 4-4-4-12 240PIN Dual Channel Memory )


    I'm definitely going to install the two corsair memory sticks. However I'm wondering if I would be loosing out by also throwing the 2048 stick into a third slot to max out my 32 bit vista home premium at 4 gigs of ram. If I put in the third stick would I loose alot of speed or my dual channel capabilities?

    What do you people recomend? I am upgrading mainly for DV rendering capability (non-linear calculations)
     
  2. X DarthMonkey X

    X DarthMonkey X TS Rookie Posts: 164

    Throwing a third DIMM into the mix should disable Dual-Channel operation, and force your high-end RAM to run at the same speed as the low-end 2048MB DIMM. Therefore leaving you with 50% more RAM, but 50% less bandwidth and 16% lower clock.

    I would avoid this scenario. Vista runs just fine on 2 gigs of good RAM.
     
  3. X DarthMonkey X

    X DarthMonkey X TS Rookie Posts: 164

    I'm changing my opinion slightly.

    I previously stated that you would get about a 50% increase in RAM (despite an actual increase of 100%). This is half true. Your computer will only "see" less than the total 4gb, depending on your hardware. The official upper limit for Vista 32bit is 4GB, but the 32bit version reserves an amount of address space equal to the total amount of memory of all your other hardware (Video card, soundcard, etc...) leaving you with that much less breathing room. The reserved address space is unusable.

    So you will be left with less than 3.5GB (512MB video card, and of course other stuff I don't know of) so about a 75% practical RAM increase. Still, no Dual-Channel and a slight speed decrease.

    The advandages are clear, but the disadvantages are also. With these new considerations, I actually think you may want to do that - go ahead and toss in that extra 2GB stick. If you don't like the performance it gives you, you can always remove it.
     
  4. captaincranky

    captaincranky TechSpot Addict Posts: 10,814   +921

    Intel chipsets with dual channel capability will run asymmetric configurations of RAM modules in what they call "Dual Channel Interleaved" mode. That means if you have 1GB in channel "A" and 2GB in channel "B" then you will have the lower 2 GB running in dual channel mode and the other 1GB will run as single channel.

    I do not know how Gforce approaches this issue, I am just posting this to clarify some preconceptions people have about the single/dual channel configuration issue.

    Perhaps a trip to their website, or a perusal of the board's manual could shed some additional light on the subject.
     
  5. arasarn

    arasarn TS Rookie Topic Starter

    easier solution;

    take my four sticks equalling 5gigs of ram, trade them at a store beside my work and give them $20 to get two sticks of 2 gig 800 mhz ram. Problem solved.
     
  6. X DarthMonkey X

    X DarthMonkey X TS Rookie Posts: 164

    I was just about to suggest that.
     
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