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I'd like to know what are the factors that need to be set in order to sustain the Dual Channel mode.

In a mobo with 4 DDR3 slots:

  1. Do I have to put pair of chips? Eg: If I put 3 identical chips only, will I have Dual channel or not?

  2. If I put 4 Ram chips that aren't from of same ventor/model, will I have the same latency among them (the highest of all)? Also, will I sustain Dual Channel mode?

  3. If one Ram has max frequency of 1033 and the other 3 chips are of 1300, will I have 1033Mhz for all chips and Dual Channel mode on?

  4. What if I put 2x4Gb and 2x8Gb chips (latency, Dual Channel)? Can I put 4Gb chips in slots 1 and 3 and 8Gb in slots 2 and 4 and still have dual channel mode enabled?

(Some of the questions might sound silly but their answers aren't that clear to me) (Also, assume that there aren't any bottlenecks because of other parts on the system)

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2 Answers

All you need is the same amount of RAM on each channel. The answer to your questions are:

  1. With 3 identical sticks, no, since one channel will have more RAM than the other.

  2. You will have dual channel if both channels have the same amount of memory. The voltage, frequency, and latency will be the best settings that all sticks support. (They have to all be the same.)

  3. You'll have 1033MHz and dual channel if the same amount of RAM is on each channel.

  4. Yes, since you'll have 12GB on each channel.

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it depends on the system board. some can do quad channel ddr others dual. some systmboards are very picky about ram being from dual channel kits while others may not care if they are the same type of memory. The official stance is it should be same type/speed of memory to keep dual channel.

memory always goes to the lowest common denominator. as for latency I dont know. q4 unless the systemboard doesnt specify other wise usually you can put multiple sized pairs in as long as the "kit" stays in the same channel.

My comment earlier about depending on the system board is due to each system board even from the same batch of the same model can act very differently. the phisical componants have a tolerance of x% meaning that no 2 products will be exactly alike causing little quarks because 1 critical capasiter etc is -1% from spec where the next is +4%. back in "the old days" we would get 4 or so identical amd p5 cpu's and 6 sets of ram out when trying to build a system because 1 processor jsut wouldent work with memory set 1345 in the systemboard. the tolerances and such are much better now so you dont find that kind of compatibility issues much any more but it still makes it so that 2 identical pc's with a corp image that was started on both at the same time complete at 2 entirely different times etc.

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