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Memory DDR2 vs DDR3

Discussion in 'Hardware' started by Dazza007, 24 Jun 2009.

  1. Dazza007

    Dazza007 What's a Dremel?

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    My motherboard takes ddr2 and ddr 3 1333Mhz, and my processor runs at 1333Mhz, now then, I'm thinking of upgrading my memory to the ddr3 1333 but on crucial.com and corsair.com they advise me to use ddr2-800Mhz. can anyone explain why this is so? surely the faster memory will match my processor's speed and give me a performance boost?

    Daz
     
  2. JaredC01

    JaredC01 Hardware Nut

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    You're better off with DDR2 RAM. The benefit of DDR3 is negligible unless you're on an i7 or the latest AMD platform.

    What CPU are you running? That may have an effect on what RAM the websites are recommending.
     
  3. Dazza007

    Dazza007 What's a Dremel?

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    E6750

    I'm running an intel C2D E6750 Socket 775 1333Mhz 2.66Ghz

    so wont the bus speed of the memory speed up the system? I'm fairly confused by this

    thanks for the quick reply
     
  4. Koolpc

    Koolpc Minimodder

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    DDR2 is probably the best to get at the mo
     
  5. JaredC01

    JaredC01 Hardware Nut

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    Hmm... There shouldn't be an issue with running 1333 RAM then. You're running a 333MHz FSB, with an 8x multiplier on the CPU (2.66GHz), which means assuming your RAM is running at 1:2 with your processor (which should be easily verified in the BIOS), you should be running 1333MHz RAM just fine.

    333MHz:666MHz DDR = ~1333MHz

    Shouldn't be an issue so long as your motherboard will run the RAM at 1:2 to the bus.
     
  6. D-Cyph3r

    D-Cyph3r Gay for Yunosuke

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    On a board that supports DDR2 and DDR3 i'd stick with DDR2, usually the DDR3 support is pretty poor and will no doubt perform worse than decent DDR2 (800Mhz+, 4-4-4-12 timings)....


    As for DDR3 vs DDR2 in general the only thing that made DDR3 so unattractive at the start was the price, but with very nice 1600Mhz kits costing as low as £60-70 now it's definitely the better option (if say you were deciding between a AM2+ or AM3 board).
     
  7. Dazza007

    Dazza007 What's a Dremel?

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    Jared all your figures are bang on there bud. i've OC it to 2.8 Ghz tho :)

    D-Cyph3r, my memory is Corsair my timings are 5-5-5-18 which I believe is not as good as the timings you've mentioned? the board I got was one of the first ddr3 boards around when i got it (that was the reason i bought it, future compatability).
     
  8. javaman

    javaman May irritate Eyes

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    Intesting topic. Since the new phenoms can run using both DDR2 and DDR3, is there any point in running DDR3 yet? at least until new chipsets are released
     
  9. JaredC01

    JaredC01 Hardware Nut

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    You hadn't mentioned that ;).

    As for the memory timings, he's referring to DDR2 800MHz timings. Higher speed RAM modules often have relaxed timings due to the increased speed. In fact, most DDR2 1066MHz kits are overclocked versions of the DDR2 800MHz modules, with relaxed timings and higher voltage to stay stable. The higher physical speed makes up for the relaxed timings (especially if you're running at 1333MHz).

    Slightly off topic...

    Occasionally you'll come across a kit of 1066MHz that won't run at spec'd settings. The RAM I'm using (in my signature) is marked as 1066MHz, though I couldn't get the RAM running stable at stock speeds. Instead of slacking the timings a tad more I dropped the multiplier to 1:1, kept the voltage at 2.1v (spec for the modules), and tightened the timings. Personal preference of mine is to run the RAM at either 1:1, or ideally 2:1. If you'd like more explanation why I'd be happy to make another post. :)
     
  10. Dazza007

    Dazza007 What's a Dremel?

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    yup

    If you wouldnt mind jared, and how do you find all this stuff out, is there a college course I can go on to learn it?
     
  11. JaredC01

    JaredC01 Hardware Nut

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    Alright, lets see if I can explain this in an easy way!

    Any and every CPU you will find has an on-board L1, L2, and sometimes L3 cache... The largest cache (usually the L2 or L3 if your chip has one) is the 'most' important cache on the chip to the consumer, and it's what affects real-world performance the most. The L2/3 cache on the chip has bandwidth, just like your RAM in your computer does.

    The main purpose of the RAM is to keep the L2/3 cache filled with instructions to be passed to the L1 cache, which then deals directly with the processor. In an ideal setup, the RAM will run at the same (or higher) bandwidth as the L2/3 cache, in order to keep the cache filled with instructions, though this can be partially substituted with larger caches and higher amounts of RAM.

    I personally like to run my RAM at a 1:1 or 1:2 divider because of two things...

    Running at 1:1 is running synchronous with the FSB, which means it's running at the same speed as the CPU cycles are. For every CPU cycle, there's a memory cycle, so everything matches up. If you were running the RAM on an off divider (3:5 for example), the CPU would end up wasting some of its CPU cycles even if the memory is running faster than the CPU. With a 1:1 you still have the bandwidth issues, though you're not wasting clock cycles on the RAM.

    Running at 1:2 isn't running synchronous, though it's running at a divider speed that will ALWAYS be there when the CPU needs it, without wasting any clock cycles. Since the RAM is twice as fast as the FSB, it can complete exactly two cycles for every CPU cycle. Since the RAM can complete two cycles for every one CPU cycle, then your bandwidth is increased dramatically. From there, I'll point back up to my earlier post about how ideally the RAM would have the same bandwidth as the CPU. Since the RAM's bandwidth is effectively doubled from a 1:1 divider, there's a much greater chance that the RAM will be able to supply the L2/3 cache with the bandwidth it needs to stay saturated. If a CPU's cache is saturated all the time, it won't matter if it's a 10MB L2/3 cache, or a 1MB L2/3 cache, it will ALWAYS be saturated, and never be waiting for instructions. Hellllooooo performance... :)

    If I could, I would run the RAM at an even higher divider, so long as the second number was an even number multiple of two (2, 4, 8, 16, 32, 64, 128, 256, 512, etc). Could you ever see RAM being run at a 1:512 to the FSB though? :)



    As for where I learn this stuff at, I either pick it up along the way, or I've had a previous experience that required me to find the answer (in this case, a bit of both). I've never had any formal computer training of any sort, and more than likely I won't ever, simply due to the fact that I can learn more from the rest of the community for free than I could paying for a class. Gotta love the internet.

    :thumb:
     
    DragunovHUN, Guest-16 and mm vr like this.
  12. mm vr

    mm vr The cheesecake is a lie

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    Rep++ fo ya, Jared! :thumb:

    I don't know anybody computer literate who has not learnt everything himself without any courses or such. When I worked in a company as an IT guy for a while, the other guy told me he was actually a cook and hadn't had any computer training, even though he was a long time worker in the IT department.

    The only way to learn is to do. Or at least the best way. :)
     
  13. JaredC01

    JaredC01 Hardware Nut

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    Appreciate the rep mm vr!

    I went to school with a few people that took computer classes at a local tech school back home, and after they got out of the class, they still barely knew half of what they thought they knew. They thought they would 'instruct' me on a few things about computers, both of which (on different points mind you) were incorrect on everything but the basics on what they were trying to talk about. The sad part? They paid $40,000 to attend the school.

    I've found there's more than enough people in the world willing to freely share information, and I use it to its full advantage! Hopefully I've helped at least a couple people with the info I've posted throughout the years, and I always appreciate the rep. :)
     
  14. Guest-16

    Guest-16 Guest

    Because the AM3 motherboards are far, far better than AM2+ ones: MSI 790FX-GD70 and 770-C45 for example. For CPUs that have a direct connection to memory, we've found DDR3 offers a greater overhead for HT/QPI performance increments.
     
  15. javaman

    javaman May irritate Eyes

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    I learnt something!!! thanks Jared =)

    Bindibadgi, can you explain HT/QPI increments fr me? Is it to do with how the processor communicates with the northbridge or an I thinking of something else?
     
  16. hotnikkelz

    hotnikkelz What's a Dremel?

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    If u're Intel, then DDR2
    If you're AMD with AM3 socket type, then DDR3
     
  17. ProDigit

    ProDigit What's a Dremel?

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    Just a quick question,
    DDR3 RAM is said to use less power than DDR2 RAM, while the DDR3 controller uses more power than a DDR2 controller.


    I've always wondered if DDR3 really would consume more or less than DDR2, but never found any benches on it.
     
  18. JaredC01

    JaredC01 Hardware Nut

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    If you look at the voltages on the DDR3 RAM, you'll notice (for the i7 chips anyway) that the maximum voltage on the modules is 1.65. My current DDR2 RAM for a comparison, runs at 2.1 volts.

    The AM3 chips from AMD can handle higher voltage RAM modules than the i7 chips, though I don't know what their max voltage is.
     
  19. Dazza007

    Dazza007 What's a Dremel?

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    I have just installed my new DDR3 and done the index test and it stayed the same, websites appear to be loading a little slower than normal, not much in it but there is a difference. and i've sold my DDR2 now, oh well you live and you learn.

    Hang on a minute, I have just gone into the bios and tweaked my memory upto EXTREME (wouldnt work on DDR2) and the system is flying. not sure how it will fair when I do heavy duty stuff but so far so good.
    According to CPU-Z my memory is running 1:2, 666.7Mhz, Clocks are 9-8-8-22. are these CL numbers terrible?
     
    Last edited: 2 Jul 2009

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