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Question: Dual channel vs. tri channel SDRAM

By milrobo
Jun 7, 2009
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  1. I just bought a Dell Studio XPS with an Intel Core i7 chip and fell into the trap of buying 8GB of DDR3 SDRAM (config 2x2GB/4x1GB), which has to be dual channel. My understanding (now) is tri channel is a better way to go. Dell will not refund or exchange sticks.

    Dell tells me that the mother board will support tri channel. Can I convert to 6GB tri channel simply by pulling out 2 1GB sticks and creating a 2, 2, 1+1 config, or would it have to be 3 2GB sticks. In the same way, could I buy another 1GB stick from Dell and create 9GB tri channel using a 2+1, 2+1, 1+1+1 config (or does it have to be 3 3GB sticks)?

    How does 8GB dual channel compare with 6GB or 9GB tri channel memory?

    Are tri channel memory sticks inherently different from dual channel sticks?
  2. Rick

    Rick TechSpot Staff Posts: 6,304   +52 Staff Member

    Firstly -- If you care about money at all, don't buy your memory from Dell. ;)
    They commonly have a 200-500% markup on their RAM. www.newegg.com is usually a good place to order from and you can use their memory configurator to make it easy (and they guarantee compatibility or your money back)

    As for triple channel memory...
    Can you use something other than 3 or 6 modules at a time? I believe the answer is no. I really don't think so based upon how multi-channel RAM actually works. It would be *technically* possible if the board manufacturer *really* wanted to do it... But I firmly doubt any board actually does support a [2+1, 2+1, 1+1+1] configuration in triple channel. I can't tell you no for sure though, because I've never seen anything that actually says you can't do it. I'd like to point out that some boards do support mixing sizes for dual channel, but it has to be (just as an example) [2+1, 2+1] or [1+2, 1+2]... The sizes need to match for each paired bank. But even under this consideration, you'd still need [2+1, 2+1, 2+1]. The config you proposed shouldn't work.

    Something else to consider is the disappointing lack of a noticeable performance increase:
    I'm all for souping up your computer, but moving to triple channel from dual channel is only useful in terms of bragging rights, really. If you're willing to drop some cash though, there are other ways of improving your system performance that will yield better gains. I wouldn't get too bent up over running *just* a dual channel memory config, though. :)

    In all honesty, 3GB is enough memory to do pretty much anything you'd like at the moment. If triple channel is THAT important, then try it out [1, 1, 1] and see if you like it. If you think it runs better -- I mean, RAM *is* pretty cheap -- you could buy another 2GB module and then maybe you can swing [2+1, 2+1, 2+1]. Personally though, I don't find the results compelling enough to do it.
  3. red1776

    red1776 Omnipotent Ruler of the Universe Posts: 5,895   +88

  4. milrobo

    milrobo TS Rookie Topic Starter

    Question: dual channel vs. triplle channel memory

    Very helpful. Thanks to both of you. I got taken a little bit but at least it won't continue. I think for now I'll just leave the memory config as it came.
  5. conehead95

    conehead95 TS Rookie

    Dual Channel vs. Triple Channel

    Wow, do I feel dumb. I am close to being computer illiterate as I do not know the technical aspects of a computer. However, I'm retired and I use a computer throughout the day for numerous tasks.

    I should have checked this site yesterday prior to ordering my new computer. I ordered the Dell Studio XPS and "upgraded" the package FROM 6GB Tri-Channel DDR3 SDRAM at 1066MHz - 6 DIMMs TO 8GB Dual Channel DDR3 SDRAM at 1066MHz - 6 DIMMs based on Dell's recommendation that this would "Help improve multi-tasking, speed up gaming, and take your PC's performance even higher with increased RAM."

    And, you all know what's coming.....this cost me an extra $100 for my computer. Today when I was looking over the contract I became curious as to why dual channel would improve multi-tasking over the tri-channel that comes "standard" on this model. This prompted me do some research that I should have done prior to making this purchase.

    Well you know what they say about "a fool and his money!" But I do care about my money and did research prior to making this purchase, unfortunately not the right kind of research.
  6. captaincranky

    captaincranky TechSpot Addict Posts: 10,678   +880

    It doesn't seem necessary to castigate oneself for following a manufacturers advice. It is reasonable to assume that the manufacturer should, (aside from making a profit), represent the product fairly and truthfully. Here is a situation where Dell is blatantly lying, and there are many pages of another thread on this topic here.

    With dual channel systems it is possible to run part of the memory in dual channel and the remainder in single channel, in what is called "flex mode". To accomplish this, you would place an equal amount of RAM in sockets 0 & 2, then the excess in the last socket of channel "B", these are the highest memory addresses. I'm not certain if "Flex mode applies to tri-channel RAM, but if I were to try make it work, I would install the DIMMs as follows, 2GB in channel "A", 2GB in channel "B", then the final 4GB in channel "C". I don't know if the modules you have will permit this arrangement.

    My "plan B" would be to keep checking for a class action lawsuit to occur aginst on this issue.
  7. red1776

    red1776 Omnipotent Ruler of the Universe Posts: 5,895   +88

    the fools are at Dell

    Yeah conehead, what Captain said. you undoubtedly remember that for years everyone said that "you cant have to much memory" well that was when a 32MB stick was $70, now you can get a 4GB dual channel set for $40. memory is cheap so dell,HP, etc make it the featured flavor of the day and talk all the BS about improving performance. when anything over 3-4 Gb is superfluous for the average user, and even most enthusiasts. I have 8GB in my machine and do alot of intensive things, and I cant come close to using it all. ......makes me wish that Google Earth had never fixed that colossal memory leak, so i could visit once in a while and feel like im getting my moneys worth! :) sorry you got screwed by Dell
  8. LinkedKube

    LinkedKube TechSpot Project Baby Posts: 4,265   +41

    Lol Red, one of my brothers manages to use 8, I hit the 10Gb mark 2 weeks ago when i bought flight simulator. Trying to download things and play music at the same time. Flight Sim got my cpu to 80% as well and my fps dropped to 20, the first time I've ever seen that. i havnt played it since :D
  9. red1776

    red1776 Omnipotent Ruler of the Universe Posts: 5,895   +88

    yes! but you are not an average user! LOL...or an average enthusiast for that matter, I hit just over 5Gb while rendering in 3ds max, downloading a game trial (1.4gb) and watching a video, but not 10gb. im curious though i play flight sim X on mine, but nothing approaching that much memory.
    Gee....80% once....i really feel for ya :haha: :p
  10. LinkedKube

    LinkedKube TechSpot Project Baby Posts: 4,265   +41

    Get a resolution of 2560x1600 and set everything to max, im convinced Flight Sim hurts my pc more than Crysis. Anyway, back to the subject.

    The only big difference between triple and dual channel is the bandwidth possibilities, but those arent even really seen until you get into synthetic benchmarks. Having more memory will be more beneficial than the speed of the memory, until you get to the point where x-> memory beyond "X" isnt being used in anything you do.
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