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Thread: RAM matching

  1. #1
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    RAM matching

    Hey guys! Again me, this time no PC problems, just some planned upgrade. I want to add more RAM modules to my PC, right now I have 2x2GB kingston 1600MHz CL9 (If I understand correct, CL9 is timing) RAM kit, now I want to another 8GB(2x4GB) of RAM for a total of 12GB RAM. By searching in the internet I found that for better compatibility I should buy RAM whith
    1. same speed (my case 1600MHz)
    2. same timing (CL9)
    3. same producer (Kingston)
    I just wanna know if my info is correct and/or if I am missing something.
    Thank you very much!

    UPDATE 1:
    After varios posts, if someone is looking to match their RAM, they should buy new RAM following these criteria:
    1. Same speed (MHz)
    2. Same timing (if you can't find same timing as your current RAM, just buy with better timing, it will easily adjust to your current RAM timing)
    3. Same voltage (here I don't know what's better: under voltage or over voltage, just try to be same voltage)
    4. This is not important, it's optional, you can even forget you saw point number 4: same producer.

    Thanks to everyone who help with my problem!
    Last edited by nichitapavel; 01-17-2013 at 10:28 AM. Reason: Providing a quick question in the first post

  2. #2
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    Re: RAM matching

    3. Same voltage
    IMO producer doesn't really matter

  3. #3
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    Re: RAM matching

    Quote Originally Posted by nichitapavel View Post
    Hey guys! Again me, this time no PC problems, just some planned upgrade. I want to add more RAM modules to my PC, right now I have 2x2GB kingston 1600MHz CL9 (If I understand correct, CL9 is timing) RAM kit, now I want to another 8GB(2x4GB) of RAM for a total of 12GB RAM. By searching in the internet I found that for better compatibility I should buy RAM whith
    1. same speed (my case 1600MHz)
    2. same timing (CL9)
    3. same producer (Kingston)
    I just wanna know if my info is correct and/or if I am missing something.
    Thank you very much!
    In this case I'd just put in the 8 Gigs and leave the 4 gigs out.

    The memory controller may not like having all of the slots populated with ram.
    Even if it did, you would have to increase the controller voltage in the bios. (just to be on the safe side)

    What are you doing with this rig ?


  4. #4
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    Re: RAM matching

    If not overclocking, I've found the memory controllers to be far more forgiving about mis-matched DIMMs than they used to be in the past. I'd say getting matched speeds, timings, and voltage is the most important three criteria to consider. You can try to use the ram in all slots, but mmettin is right, the memory controller might give you issues. If not, great, but you can easily test by removing the old modules, or swapping slots. I'm not sure if memory controllers with mixed dimms prefer matched dimms on the channel, or matched capacity (i.e. 2x4GB modules on channel A and 2x2 on channel B vs 1x2gb and 1x4gb on each channel)


    Trust me, I do science
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  5. #5
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    Re: RAM matching

    Quote Originally Posted by mmettin View Post
    In this case I'd just put in the 8 Gigs and leave the 4 gigs out.

    The memory controller may not like having all of the slots populated with ram.
    Even if it did, you would have to increase the controller voltage in the bios. (just to be on the safe side)

    What are you doing with this rig ?
    General home usage, a little bit of codding and some gaming. I would like to keep my old 4GB, other wise they just get dust around my house (if you know what I mean).

    Quote Originally Posted by Activate: AMD View Post
    If not overclocking, I've found the memory controllers to be far more forgiving about mis-matched DIMMs than they used to be in the past. I'd say getting matched speeds, timings, and voltage is the most important three criteria to consider. You can try to use the ram in all slots, but mmettin is right, the memory controller might give you issues. If not, great, but you can easily test by removing the old modules, or swapping slots. I'm not sure if memory controllers with mixed dimms prefer matched dimms on the channel, or matched capacity (i.e. 2x4GB modules on channel A and 2x2 on channel B vs 1x2gb and 1x4gb on each channel)
    I'm am not overclocking in the real sense of overclocking, details bellow.

    When I saw reply about more important is VOLTAGE than producer, I realizaed I didn't know at what voltage my RAM is working, on RAM modules there isn't a explicit mention of voltage but it does say: "1.7-1.9V", so I went into BIOS and looked at it, MIN = 1.5V, MAX = 2.205V, Standard = 1.5V and set at AUTO, if my assumptions are correct I'll have to buy 1.5V RAM.

    Another "problem" that I found, by default my memory works at 1333MHz at CL9 timings, in order to get it to work at 1600MHz I go into BIOS and change it, but this also changes my timings to CL11. Bellow are some screenshots, first at 1333MHz, second 1600 MHz, voltages remain the same, min, max, standard and auto.

    https://skydrive.live.com/redir?resi...Kt5-ew0tBgwVxA

    https://skydrive.live.com/redir?resi...ByczeFHNjwnlFo

    Now my question is, do I buy RAM with 1600MHz, 1.5V and CL11 timings or the same with CL9 timings?

  6. #6
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    Re: RAM matching

    Can we get the rest of your system specs?


  7. #7
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    Re: RAM matching

    Quote Originally Posted by mmettin View Post
    Can we get the rest of your system specs?
    Of course:
    MB: Asus M4A77TD
    CPU: AMD Athlon II X4 630
    GPU: Nvidia GTX 8500 (in the comming weeks I'll buy an 7850 2GB)
    RAM: 4GB(2x2GB) Kingston HyperX
    Power supplie: Nox Urano 2 530w (in the comming weeks I'll buy a new, possibly Corsair CX 600)
    SSD: OCZ Vertex 2 3.5inch and 2 HDD but I don't thing they matter, Windows is on SSD.

  8. #8
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    Re: RAM matching

    Is there a monitoring page in bios? A lot of times those pages report the various voltages, so you should check the vdimm value there. here are pretty much 2 standards for ddr3: 1.65v and 1.5v. My guess is that if the dimms are saying "1.7-1.9", that means 1.65v. I would try to get CL9 memory in any case, because ram will usually work just fine at looser timings than its specced for. If you get RAM thats faster than your old ram, it should default to the same speed as the slower RAM.


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  9. #9
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    Re: RAM matching

    Quote Originally Posted by Activate: AMD View Post
    Is there a monitoring page in bios? A lot of times those pages report the various voltages, so you should check the vdimm value there. here are pretty much 2 standards for ddr3: 1.65v and 1.5v. My guess is that if the dimms are saying "1.7-1.9", that means 1.65v. I would try to get CL9 memory in any case, because ram will usually work just fine at looser timings than its specced for. If you get RAM thats faster than your old ram, it should default to the same speed as the slower RAM.
    There is a monitor page in bios, but it doesn't says a word about vdimm.

  10. #10
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    Re: RAM matching

    I played a little bit with my BIOS settings, I put speed at 1600 MHz, voltage changed to 1.65, and I changed timing more closely to CL9 (more exactly CL = 9, tCRD = 9, tRP = 9, tRAS = 24, tRC = 33). With these settings I consistently got better performance, a very small but still an improved over auto settings, also with this settings I consistently got latency of 55ns, in all other scenarios latency was above 60ns. For benchmarking I used PassMark software PerformanceTest.

    My Conclusion after these test is: I should by RAM with 1600MHz speed, CL9 timing and 1.65 voltage. Please share your opinion!

  11. #11
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    Re: RAM matching

    Quote Originally Posted by nichitapavel View Post
    I played a little bit with my BIOS settings, I put speed at 1600 MHz, voltage changed to 1.65, and I changed timing more closely to CL9 (more exactly CL = 9, tCRD = 9, tRP = 9, tRAS = 24, tRC = 33). With these settings I consistently got better performance, a very small but still an improved over auto settings, also with this settings I consistently got latency of 55ns, in all other scenarios latency was above 60ns. For benchmarking I used PassMark software PerformanceTest.

    My Conclusion after these test is: I should by RAM with 1600MHz speed, CL9 timing and 1.65 voltage. Please share your opinion!
    I would agree with that assessment


    Trust me, I do science
    My Hardware, Past and Present

  12. #12
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    Re: RAM matching

    Quote Originally Posted by Activate: AMD View Post
    I would agree with that assessment
    Thank you for sharing your opinion!

  13. #13
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    Re: RAM matching

    Thanks everyone for your help!

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