32bit OS and RAM question

Discussion in 'Hardware' started by dlb, Mar 26, 2009.

  1. dlb

    dlb MajorGeek

    I know that 32bit operating systems have a limit of 3.2gb or 3.5gb of memory due to architectural design limitations. My current memory is set up in dual channel, 2 x 1gb DDR2 and 2 x 512mb DDR2 for 3gb total. If I installed 4 x 1gb (or 2 x 2gb) I know WindowsXP would only address 3.2gb or 3.5gb, but would this effect the dual channel operation? I'm thinking that because of the 32bit RAM limit, the amount of memory in each channel won't be exactly even and would therefore 'disable' the dual channel mode. Currently, I have to put both 1gb sticks in channel A, and both 512mb sticks in channel B to enable dual channel mode. If I installed 4gb, but only 3.5gb is actually addressed, does the 'extra' unused memory throw dual channel mode out-of-whack?

    :-D

    Thanks!

    (one other question -probably should start a new thread- but what's the deal with "64x8" memory versus "128x8"?)
     
    Last edited: Mar 26, 2009
  2. FieroGT42

    FieroGT42 Private E-2

    Idk, but that's a very good question. I'd like to know myself, just for curiosity's sake.

    As for 64x8 vs 128x8 and all that, it has to do with the density. I'm too lazy to explain it all, but you can read pages like this or this. If you want to learn more, just Google some of the terms you find there, maybe add "memory density". In general, all computer will be able to use low density, but not all support use of high density.
     
  3. dlb

    dlb MajorGeek

    :confused Nobody??? Hmmmm.... I guess I'll just have to try it and see what happens... I will report my findings so we can all learn something new....

    ;)

    (thanks for the above info about RAM density, I didn't know the 'official' terminology)
     
  4. dlb

    dlb MajorGeek

    Well, I still haven't tried installing 4gb to see how it effects dual channel memory mode on a 32bit OS.... I was kind of hoping someone with knowledge on this would post here.... so, I guess technically, this post is a bump. rolleyes :-o

    LOL
     
  5. Borsung

    Borsung Corporal

    Just buy a 64bit OS and solve all your problems :\

    My PC is screaming fast on a 64bit OS
     
  6. Just Playin

    Just Playin MajorGeek

    I've never tried it but the dual channel mode is a function of the BIOS, independent of the operating system. It should work.
     
  7. tunered

    tunered MajorGeek

    I think the bios has nothing to do with dual channel, intel uses a controller on the motherboard while amd is made within the processer. ed
     
  8. Mimsy

    Mimsy Superior Imperial Queen of the MG Games Forum

    Apologies for being late to the thread. Family medical issues were happening. :)

    BIOS has next to nothing to do with dual channel. That is determined by the memory controller on your motherboard. If you have a dual channel board it runs identical pairs of memory in dual channel. Just keep the 1GB ones in the blue slots, and the 512MB ones in the black (or whatever color they are).

    However, dual channel is also independent of the operating system, so 2x2GB in dual channel will be faster than 3x1GB in single channel. I wrote a sort of explanation on the issue of 4GB in 32-bit a while ago, if you're interested.
     
  9. dlb

    dlb MajorGeek

    OK... here's the deal (if anyone still gives a :crap ).... I had 3gb in dual-channel (2 x 1gb and 2 x 512mb) and I just pulled all four sticks and replaced 'em with 2 x 2gb (the old ones were generic DDR2-533, these new ones are Kingston DDR2-800). Even though my 32bit XP Pro only address 3.25gb, it does still function in dual channel mode. I was concerned that the "extra" unaddressed memory would throw off the dual channel, but it didn't. As we all know, for dual channel to work, the memory has to be in matching pairs, and apparently 2 x 2gb is still a matching pair even though 32bit OSes don't address all of it.
    :-D

    [dlb]

    (for those of that might care, I got a 4gb 'kit' and the sticks are low-profile; if you have a monster CPU cooler, there's no chance the RAM will get in the way; Kingston part number KVR800D2N5K2/4G )
     

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