Dual Channel ??? How do u know?

Discussion in 'MacBook Pro' started by iMetalG5, Jan 20, 2010.

  1. iMetalG5 macrumors 6502a

    Joined:
    Apr 13, 2005
    #1
    Ok so my brother just got a 13 MBP 2.26. He wants to upgrade the RAM to 4GB. He used a gift card to buy the following:

    KINGSTON KTA-MB1066/2GR @ a rip off price of $124!!!!!! but since he had a $150 gift card he did it.

    Now he has a friend that bought the same exact RAM as above and gave it to him. He now has a total of 4 GB of RAM.

    Will this run in Dual Channel? I'm not sure but he said they are identical just not bought as a "kit"

    I told him to return it as he could get Crucial 4 GB kit for $115!!!!!!
     
  2. m85476585 macrumors 65816

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    Feb 26, 2008
    #2
    Modern laptop chipsets allow "asymmetric dual channel" memory access, so unmatched memory modules give you very little performance reduction, maybe a few percent. I benchmarked my memory after going from 4gb (2 matched modules) to 6gb (unmatched), and the difference was within the error of the benchmark.
     
  3. iMetalG5 thread starter macrumors 6502a

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    Apr 13, 2005
    #3
    hmmmm ok. well he said he can return it even if opened so maybe we should test it out. he's on his way over now. and he sent me pics of the RAM and the two packages look identical. I know Kingston is good stuff but $124 each?
     
  4. m85476585 macrumors 65816

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    Feb 26, 2008
    #4
    That sounds expensive. The going price for 2x2gb 1066 DDR3 is about $100 online. As long as the memory has the right specs, comes from a reputable manufacturer, and has a lifetime warranty, there really isn't any difference. The only exception is if you pay more for a lower latency, but I don't know what latency MBPs support. In that speed, most RAM has a latency of 7, but some of them have a latency of 5. Getting CL5 instead of CL7 might give you a small improvement in benchmarks, but will almost never be noticeable in real-world use.

    The RAM he has is CL7, and it is best not to mix modules with different latencies (or any different specs for that matter).
     
  5. iMetalG5 thread starter macrumors 6502a

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    Apr 13, 2005
    #5
    well we did the install. Took all but 5 mins. Here is the exact RAM he bought.

    http://www.bestbuy.com/site/Kingsto...174;/9146667.p?id=1218035197495&skuId=9146667

    the packages were identical. I have NO IDEA why they are charging $124 EACH for this RAM. Why anyone?????

    We started his 13 2.26 up and damn its fast!!!!!! went into "About this Mac" and it shows 4 GB. Went into more info and it shows both slots as 2 GB.

    is there anything else we can do to test the RAM? He's very happy right now and I say since he did not pay for this RAM mine as well keep it. But again why is Kingston RAM so expensive????

    If there really is a difference in buying say Crucial 4 GB Kit then I will tell him just to return the 1 pk of 2 GB RAM to Best Buy and give the other one back to his friend.
     
  6. m85476585 macrumors 65816

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    Feb 26, 2008
    #6
    It's expensive for 2 reasons:
    1. it's "Apple RAM". I don't know what that means--normal RAM will work just fine in macs. I use normal RAM in my MBP, and so do many users here.
    2. It's from Bestbuy, and their prices are a ripoff. Ever try buying a HDMI cable there? They want to sell you one for no less than $60, when you can get something functionally the same online for $5-10.

    Here's the exact same RAM from Newegg, $55.
    http://www.newegg.com/Product/NewProduct.aspx?Item=N82E16820134832

    There really is no difference between major brands of memory as long as they have the same specs (unless you are overclocking, but that's not possible on most laptops). Crucial RAM is just as good as Kingston, and usually similarly priced. In fact, there are only a few companies that make the actual memory chips even though there are many companies that will solder those chips to modules and put their name on them. Back in the old days of DDR2 and extreme overclocking, everyone wanted Crucial RAM because their Micron chips were known to be some of the best. That's not the case any more, but Crucial is still a reputable RAM manufacturer.

    Personally, I have had a good experience with Crucial's support. I had some old modules die for no apparent reason, giving me tons of errors and corruption and crashing my computer all the time. I called Crucial, and after some quick troubleshooting they replaced the defective modules and the other two non defective modules (also Crucial) to for compatibility.
     
  7. iMetalG5 thread starter macrumors 6502a

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    Apr 13, 2005
    #7
    well my bro has been using his upgraded MPB 2.26 and he claims there is a HUGE difference when using Photoshop and iMovie and generally he "thinks" its very quick now. Granted I would not know as mine is the 15" 2.8 and I never used a 2.26 with 2 GB RAM. So he's gonna keep it. He still has to pay his buddy $30 for the RAM though. Overall not a smart buy. Granted he used a gift card to buy that rip off RAM but still.

    I do not shop at Best Buy and don't plan on it! :D I still can't get over that price. I mean its MORE MONEY than the Apple Store!!!! I thought for sure it was an error but its not.

    I was just wondering how can you test the latencies.

    that's messed up that Newegg has it for $55 a piece and Best Buy sells it for $124 a piece, wow that is just plain robbery rip off!!!!
     
  8. m85476585 macrumors 65816

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    Feb 26, 2008
    #8
    It should be faster if stuff was swapping to the hard drive before. RAM is orders of magnitude faster than the hard drive, so if his computer is using the hard drive less often more RAM should make a huge difference. The speed of the RAM almost doesn't matter for most tasks because it is so much faster than the hard drive.

    There are Windows utilities like CPU-Z that will tell you what latency your RAM is configured for. Normally the latency is listed in the RAM specs, and for most DDR3 1066 the latency is 7. There isn't really any way to change the latency on laptops, but it is possible to adjust on desktops that can be overclocked.
     
  9. gguerini macrumors regular

    gguerini

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    Jun 28, 2007
    #9
    So the lower the latency the better (at least for benchmarks purpose)? Is that correct?
     
  10. m85476585 macrumors 65816

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    Feb 26, 2008
    #10
    If everything else is equal, yes. In simple terms, latency is the number of clock cycles it takes to access an address in memory.

    If you are looking at two RAM modules with different speeds, you have to consider the speed and the latency. For example if you have 800MHz RAM with a latency of 4, it might be just as fast as 1600MHz RAM with a latency of 8. Of course it's not that simple, but it might help to think of it that way.

    http://en.wikipedia.org/wiki/CAS_latency
     
  11. iMetalG5 thread starter macrumors 6502a

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    Apr 13, 2005
    #11
    actually when you get a "kit" with 2 pieces of RAM, how do you know they are really paired? My friend said when he bought a "kit" from Crucial he wasn't sure how to base how "identical" the pair really were. When he looked at the sticker on it he said the numbers were nowhere near sequential at all. Said they were way off - even random.

    I would assume there really is no way to figure out how identical a pair of RAM is in a kit?

    I stopped by my local Best Buy and found the same Kingston RAM my bro just bought. I took it to a Geek Squad specialist and asked him if I were to buy these two at $124 each will this run in dual channel memory? The kid said "Of course, they are the same specs" and then I asked why they don't just sell the kit and he claims there is no kit. Said this is "special Apple RAM that is superior to the Apple RAM you would buy at Apple Store"!!!!!!!!!!!!! uhhhhhhhhhhh. he then went on to say this is some of the best RAM you can get and that is why its $124. Wow. i didn't have the heart to tell him off. he really believed that.
     
  12. TheWelshBoyo macrumors 6502

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    Dec 14, 2008
    Location:
    Cardiff, Wales
    #12
    Why would it not work just because it wasn't from a kit?
    They're exactly the same model of RAM chip.
    The pairing is done due to them being the same specification and probably the manufacturer. Doing it as 2 separate chips should have no consequence on speed.
     
  13. Bill Gates macrumors 68020

    Bill Gates

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    Jun 21, 2006
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    127.0.0.1
    #13
    What the kit really does is make it such that the manufacturer will guarantee that the memory will run in dual-channel mode.
     
  14. iMetalG5 thread starter macrumors 6502a

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    Apr 13, 2005
    #14
    hey guys my bro's macbook pro 13 died. well it did not die but the RAM is faulty. he returned it to Best Buy and went online and ordered from OWC instead. $109 for 4GB is more like it. I however don't know much about OWC as I like Crucial but almost everyone I know uses OWC today. So it can't be that bad.

    Live and learn.
     

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