Strange RAM Issues

I've just got a new system and it is causing some odd issues I'm finding difficult to correct.


Intel I7 870 @2.93GHz
4x 2GB Mushkin Essentials DDR3 RAM at 9-9-9-24
Corsair TX650W PSU
Nvidia GTX 480
ASUS P7P55LX motherboard 1156

Alright so this board has got 4 DIMM slots to work in dual channel.
It seems to work fine when using either

1 DIMM in any channel A slot
2 DIMMS in channel A
1 DIMM in channel A and 1 in channel B
2 DIMMS in channel A and 1 in any channel B slot

If I try to boot up system using 1 DIMM or 2 DIMMS in channel B only (none in channel A) I get a continous red light on MEMOK! indicating a memory issue and nothing else occurs. According to what I've read in motherboard manual it should still boot using either channel B slot with 1 DIMM or with 2 DIMMS in channel B.
Using all 4 DIMMs does not give a red light but it either freezes while loading operating system or works for a bit before a blue screen and a restart.
I think maybe board is faulty but it's weird that channel B slots work when there is 1 or 2 DIMMs also in channel A
Could anyone suggest any solutions before I send it back claiming faulty motherboard or CPU memory controller?
17 answers Last reply
More about strange issues
  1. Welcome to Tom's Forums! :)

    ref - ASUS P7P55 LX -

    RAM should be installed in 2 sticks A1/B1 {Blue Slots} ; CPU | A2 | A1 | B2 | B1 |
    Each Set needs to be kept together MATCHED, and I assume the Mushkin were ONLY purchased in a MATCHED-SET of 2 or of 4; if they were purchase individually then EXCHANGE them for sets.

    Please post the EXACT Part-Number of the Mushkin's e.g.
  2. I bought system pre built so assume it was a matched set of 4 as they are all same make, speed ,model etc.
    I realise it should primarily be populated in A1 and B1 however it should still boot using A2 OR B2 I believe.
    I've ran memtest86+ on all sticks, no issues. I just think it's strange how problems only occur using all 4 DIMMS. if it was a complete channel failure I would of thought it would fail with 3 DIMMS (I realise I shouldn't use 3 but for testing purposes)?

    Part number 991586=
  3. ^Those are NOT matched-sets; they are individual sticks and NOT meant to be placed in Dual Channel or Quad Channel. RAM is matched into sets by BIN {timing/testing} and even off the same line are tested and sorted in to SEVERAL BINs. Sets aren't put together just for the 'fun' of it or to cost you extra money.

    [fastest] BIN 1 / BIN 2 /....BIN 6/ [slowest] then Matched sets are packaged from -> BIN 1...BIN 6 {BIN 1 + BIN 1}....{BIN 6 + BIN 6}. If you put A1/B1 {BIN 2/BIN 5} and/or A2/B2 {BIN 3/BIN 1} then you'll get everything from instability to BSOD to BIOS shutting down a DIMM slot.

    Whoever 'pre-built' your system was dumb to sell it; if they put 1 stick in A1/A2 and 'break' the Dual Channel well then that was simply bad for you and bad for business.

    Unfortunately, your MOBO is not listed with Mushkin Configuration
    Therefore, I would contact Mushkin or you 'Builder.'
  4. They said it was working, it was 4 DIMMS they put in.
    I've changed DRAM Voltage to 1.5v and IMC voltage to 1.25v and it's been working for an hour so far with no blue screens or freezes. Everest was claiming it to be at 1.7v on DRAM voltage before which I found a bit odd. It is set to auto in BIOS.
    I appreciate what you say about matched sets however as it works in these combinations I think it should be compatible.


    Your thoughts?
  5. BIN ISSUE as I described above, tell them to read this post and Google "Matched Pair +RAM" start at ->

    Otherwise 'ignoring reality' I would raise the following:
    QPI/DRAM {IMC Voltage} Core Voltage 1.1~1.35V (raise only until stable)
    DRAM Voltage = 1.5V

    My thoughts would be you RAM is not getting enough power for the 4-DIMMs to achieve proper power.
  6. Raised voltages to what I believe is safe.
    Still getting blue screens from memory management to IRQL not less or equal and trying to write read only memory to something etc
    I'm pretty sure it is something to do with either motherboard or memory. Those red memok! lights from only channel B memory being populated worry me enough to think it's a faulty motherboard
    I'm going to send it back
  7. Okay - it's not a BAD DIMM slot from what you posted:


    Covers all DIMM slots... :whistle:
  8. Yep you're right. However I still think it's weird when I use only channel B slots it does not work and continously lights red in memok! It should boot with just 1 DIMM in any slot including channel B or 2 DIMMS in either channel including channel B so I really don't know if it's motherboard or faulty CPU memory controller. Would you like me to post some minidumps?
  9. FREE'ish Test and it will either confirm or deny the MOBO:

    Go to your local Computer Store with a GOOD return policy and pick-up 2x{2x2GB sets} or {4x2GB set} and TRY the RAM on for size. It's a heck of a lot simpler than tearing down your rig 'potentially' needlessly. Pop them in it it works - you'll know. Return the RAM or whatever... you can tell them the 'Guy' gave you the wrong RAM and you ordered new RAM online and don't need it. ;)
  10. I've got some older DDR3 1333 RAM which I know works. I've got 3 DIMMS of this. I am going to try 3 of these DIMMS with 1 of new ones and see if it is stable.
    If not I am sending it back as I've got warranty and they can work out what problem is
  11. Mixing the RAM probably won't work.

    Sooooooo what happened...??
  12. Well
    4 hours on using 2 DIMMS from old system in channel B and 2 of new DIMMS in channel A and no freezes and no blue screens using stock voltage (auto in BIOS). Ran Intel Burn Test and prime95 for a bit and played some games. Looks like it might be fixed. Still not 100% sure yet, need to see how it continues to go.
    I guess I should be asking for some new DIMMs..?
  13. Duh, what do you think I'll say - YES! I 'personally would replace them all with (2) SETS!

    Good Luck! :)
  14. Yes I've suggested this to company. I still don't know if it is a problem with DIMMS or if it is a problem whenever I go over 6GB
    For example
    It seems to work fine currently with all 4 DIMMS populated as
    A1=New DIMM (2GB)
    B1=Old DIMM (1GB)
    A2=New DIMM (2GB)
    B2=Old DIMM (1GB)

    As you know it does not work with 4 new DIMMS of 2GB each
    Do you think it is a problem somewhere with DIMMS or more to do with 8gb?
    Cheers for all your advice
  15. ^ You're mixing them in the channels. A1/B1 {set 1} & A2/B2 {set 2}; the manual is clear as mud.

    RAM should be installed in 2 sticks A1/B1 {Blue Slots} ; CPU | A2 | A1 | B2 | B1 |
  16. So it should be two new DIMMS in A1 and A2 and two old in B1 and B2? Or is it right as it is. After 5 hours it is still working so I think it is fine as it is. I think I just need some new DIMMS as all 4 new ones don't work properly when populated with all 4 yet it does work properly with 2 new and 2 old as 4 populated DIMMS. I am just interested to know if it is new DIMMS causing a problem or whether I only get a problem exceeding 6GB of RAM.
  17. Proper Installation
    A1/B1 {set 1} NEW
    A2/B2 {set 2} OLD

    Right NOW you're Jerry-Rigging = Oddball Results.

    It's VERY important to get the RIGHT RAM; read carefully what I've been saying all along. You cannot simply chuck ANY RAM into your rig and 'hope' it works. I go thought this SEVERAL times per day.

    Use: 1. Certified RAM {QVL}, 2. Tested per RAM Mfg, 3. Approved per Ticket to RAM Mfg; AND ALWAYS buy 'MATCHED' SETS.
    Example Corsair Tested ->

    Notice my motto 'Do it Right...'

    4 x DIMM, Max. 16 GB, DDR3 2200(O.C.)*/1600/1333/1066 Non-ECC,Un-buffered Memory
    Dual Channel memory architecture
    Supports Intel® Extreme Memory Profile (XMP)
    *Hyper DIMM support is subject to the physical characteristics of individual CPUs. Some hyper DIMMs only support one DIMM per channel. Please refer to Memory QVL for details.
    *Refer to or this user manual for the Memory QVL (Qualified Vendors Lists).
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