Using 6GB RAM instead of 8 due to a mistake, is this still okay?

  1. Hello. I need your honest opinion. This is very interesting and COULD BE detrimental to my computer regarding RAM...

    For a couple of years now since I built my own ASUS P5Q system, I have been using a total of 4GB of RAM (Corsair XMS2 4GB 2x2GB modules; TWIN2X4096-6400C5) since I was using Windows XP 32-bit at the time. As you know, that is the max. amount of RAM that XP can use for 32-bit (Technically, just over 3 GB.). Several months ago, I upgraded to Windows 7 Professional with 64-bit. Since then, I even purchased more memory, exactly the same type and design I am currently using. The only difference is that the new twin RAM kit is labeled version 6.1 and my original twin RAM kit is labeled version 3.1. Both new and original RAM kits ahve the same 1.80 V ratings labeled on each module. I know my ASUS P5Q can handle up to a max. of 16 GB, so I figured I would take it to 8 GB having 2 sets of 2 kits of the TWIN2X4096-6400C5 modules. So I installed them. For the few months I had 8GB of RAM, the system ran fairly okay most of the time (say 95% good) except for playing longer online videos (like from YouTube) where the system would BSOD and/or the system would freeze during playback (later in the playback). Other than that it ran great. The system seemed more perky than 4 GB! I never modified the BIOS and left everything on "Auto" configuration (like timings and voltages) even after installing the added 4 GB of RAM. However, I never had this random freezing and BSOD happen before since I installed the additional RAM. It always ran great with only 4GB. I have been putting up with this issue for months. Then I decided to get to the bottom of it. I ran Prime95 Torture Test and other software tests to see what the issue was. The system froze exactly 6 minutes into the Prime95 test each time. I decided to take out the added 4 GB of RAM (left with 4 GB) and ran Prime95 and the tests ran smoothly. I played longer online videos with only 4GB of RAM. The videos played smoothly too.

    One of things I did is that I looked into ASUS User Guide and RE-CHECKED the QVL (Qualified Vendors Lists) for compatible RAM. I realized I misread the module type in the QVL list before I purchased the same RAM kit thinking just adding another 4 GB to my system would be fine since I know my motherboard can handle up to 16 GB. According to the QVL list, for my type of modules I ALREADY HAD, I CAN NOT add anymore modules. For DIMM socket support per QVL list, these modules do NOT support FOUR modules inserted into both the yellow and black slots as two pairs of dual-channel memory configuration. *ONE* RAM kit only supports *ONE* pair (TWO modules) dual-channel memory configuration per QVL list. WELL, THAT MIGHT EXPLAIN THE ISSUES!!!

    Well. I cannot get a refund now and I am stuck with the modules. I wanted and needed more memory too. At 4 GB of RAM, running Prime95 uses ALL the 4 GB of RAM. Also, I do video editing and needed a little more RAM anyways. So I got curious! What if I just install ONE of the TWO modules in the RAM kit (or only add 2 GB) to the already installed 4 GB of RAM for a total of 6 GB of RAM? I would have more RAM (greater than 4 GB)! Would that be okay? BUT WOULD MY SYSTEM BE STABLE??? I knew that my system was "fairly" stable at 8 GB most of the time. Lowering to 6 GB, but more than 4GB MIGHT be a good choice.

    I added ONE 2 GB RAM module to the second DIMM slot between the other pair. I ran Prime95 at 6 GB of RAM since Prime95 always seemed to catch issues. RESULT: NO ISSUES!!! Prime 95 ran smoothly. I notice that using 6 GB of RAM, I was left with at least 50% free unused RAM even using labor intensive Prime95. I figure I should be fine for video editing now. I have ran several long You Tube videos for testing purposes. NO SYSTEM FREEZES EITHER!!! I figure my system is stable at 6 GB of RAM FOR A SHORT TIME NOW. My system seems more perky now than with just 4 GB of RAM. I did not make any modifications to my BIOS either.

    What is your honest overall opinion of this scenario??? Do you think I am okay or not with 6 GB of RAM???

    Please reply!

    Thank you!

    Some basic general stats of my system:
    - Windows 7 Pro 64-Bit.
    - Intel Core 2 Quad Q9550 -- Yorkfield 2.83 GHz 1333 MHz processor.
    - ASUS P5Q desktop motherboard.
    - 6 GB of Corsair XMS2 3x2 GB DDR2 RAM.
    - XFX Radeon HD5670 GDDR5 1GB RAM Graphics Card.
  2. red1776

    red1776 Omnipotent Ruler of the Universe Posts: 5,867   +74

    hi Monte,
    Ram is one of those things that either works or doesn't when you mix it up (gee..that was profound ey?). If it is functioning and having the desired 'Zip' to your system then you're good. I am assuming from your comments that they are running the same timings, voltages etc?
    If its working then your good to go. It's always the best idea to match ram modules exactly, but a vast majority of the time they will play together rather well. I have seen some completely mis-matched ram modules work in tandem. The Asus boards of that generation were a bit more finicky than most when it came to ram type and manufacturer.
    ****do the new and old memory modules have the same CAS latency? if not, that may be the problem with running with all four Dimms occupied. you should match the CAS of all the modules, as well as the standard timings if you can. If say the first set was installed with 9-9-9-..., and the second was running 8-8-8-... for example you might change that and try 8GB's again.
    You might also check your MB manual for different memory configurations to make sure you are not giving up dual channel function from the third module being paired up. you may be able to run the third module in a 'flex' mode.

    here is a PDF version of your MB manual if you need it:
    http://support.asus.com/Download.aspx?SLanguage=en&m=P5Q&p=1&os=
  3. montecarlo1987

    montecarlo1987 Newcomer, in training Topic Starter

    Hi red1776! To answer your question, yes, I have not touched the BIOS settings at all at 6GB of RAM. Things appear stable at 6 GB. The BIOS settings on the ASUS P5Q are all by default set to "Auto". That is not the case at random rare times with 8 GB RAM intalled. Yet, I never modified the BIOS either. yet, like I said, THE QVL list for RAM indiciates that the SAME 2 kits of RAM I have (see above, each 2 GB for a total of 8GB - 4 modules) can NOT be done! Only 1 kit set or a total of 4 GB of RAM based on these types of modules with my particular motherboard. But I am trying to "stretch it" and get a little more RAM if I can without natural system issues to occur. I would love to go to 8 GB for good, but this is when the issues develope and I think I am pushing my system wrongly with the 8 GB REGARDLESS if I could tweak my system per the QVL list RAM choices. Your thoughts?

    Answer: I think so. The timings are: 5-5-5-18. The old and new modules are identail in appearance. They all are 1.80 V. The only difference is the older set/kit is 3.1 version stated on it and the newer set/kit is 6.1 version.

    This is what my ASUS User Guide states in regard about your topic:

    "You may install varying memory sizes in Channel A and Channel B. The system maps the total size of the lower-sized channel for the dual-channel configuration. Any excess memory from the higher-sized channel is then mapped for single channel operation."

    So... ...I take it to mean that since my ASUS P5Q has 4 RAM slots called Channel A that is DIMM_A1 and DIMM_A2 (These are paired together in terms of proximity -- yellow and black slots.) and likewise Channel B that is DIMM_B1 and DIMM_B2, where Channel A has 4 GB installed and Channel B has 2 GB installed; I STILL HAVE SOME *DUAL* channel configuration for both channel slots DIMM_A1 & DIMM_B1 since Channel B is smaller than Channel A and Channel B determines the minimum mapping for dual channel configuration. The excess RAM (2 GB) in the Channel A (DIMM_A2) is the SINGLE channel mapping configuration. So I have BOTH kinds of mapping channel configurations. I guess it is nice my system can do both and not just stick with complete single channel mode.

    Reply of you wish.

    Thanks!
  4. mpsteel

    mpsteel Newcomer, in training Posts: 16

    Just a quick question, when you where running 8gb of ram what was your arrangement. Which modules did you have in DIMM_A1, DIMM_A2, DIMM_B1, DIMM_B2,

    I would suggests trying all the new modules in A1,A2 and your old modules in B1,B2. you might even have to increase the timings for stability.

    On my last computer i had 2 different kits from two different vendors running in dual channel, i adjusted my timings to suit my older memory and never had a problem.

    Cheers


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