Bad RAM, or Incompatability with MOBO?

Discussion in 'General Hardware' started by krazymagic, Oct 10, 2019.

  1. krazymagic

    krazymagic Guest

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    So the system is an i7 7700k on the MSI z270A-Pro Motherboard. Ive got a stable 5.0ghz overclock on the 7700k and the system has worked well for the past year and a half. I was running some fairly cheap DDR4-3000 Patriot Memory at 16-16-16-36 timings 16GB (2x8gb). The ram was solid at this, which was its XMP, but wouldn't overclock at all. I decided to remedy that last week. With Samsung B-die being discontinued and starting to dry up in the market I decided to get a new set of RAM with samsung B-die. I went with G.Skill Ripjaws 3200mhz 14-14-14-34 32GB (2x16gb). During the shopping process I clearly remember looking at the QVL List on both the RAM and MOBO and saw that they should be compatable. I now question my sanity as now that Ive run into problems, a recheck of the QVL lists yesterday show that the RAM is not listed on the Mobo's list, and the Mobo is not listed on the RAM's list. While that isnt always significant, I think in this case it has been. I swear I saw the opposite last week when I purchased it, but I clearly goofed when looking at the list, perhaps I got the RAM model number a little wrong, as a lot of G.Skill's product numbers are very similar.

    Needless to say, as the RAM arrived I was not anticipating it not working. I was excited, as someone who has built and overclocked systems for over 20 years now, to have my first go at the legendary Samsung B-die. I slapped the Sticks in, set them at XMP and went straight into windows. Ran a quick little benchmark, loved what I saw, then rebooted to begin tweaking and running memtest86. I discovered the problem quickly. My very first memtest pass at XMP yielded errors in test 6. I was a little suprised but thought I could get in bios, adjust some voltages, make some tweaks and get it going. I wont go into all the details but I spent the next many hours going from BIOS to Memtest86 making quick adjustments, then checking test 6, as it was the consistent test where errors were popping up. I continued my testing into a 2nd day. To keep my post short I will post some bullet points of my findings, and hopefully start a discussion on what others thing is going on here. I have my own thoughts but wanted to engage some other hardware gurus. As a little disclaimer here also, I will know the answer to this dilemma 100% tonight, as I ultimately decided to buy a new mobo and cpu which will arrive today. (MSI MEG Z390 ACE + i7 9700k)

    So this is what I learned:
    • The RAM is not stable at anything above 3000mhz 14-14-14-34 with both sticks installed, even though XMP is 3200mhz 14-14-14-34, and this is Samsung B-die!
    • The RAM will not even post at anything over 3333mhz, no matter the timings. Even at 19 cas it will not post beyond 3333mhz.
    • If I pull one stick, and leave one stick in, I can all of sudden post at 3600mhz 16-16-16-36 timings, and run and pass all stress tests - again on a single stick. The PC will not even post at this same set of speed and timings with 2 sticks in. This leads me to believe the RAM is not actually bad or faulty.
    • With both sticks installed in dual channel, if I tell memtest86 to use round robin instead of parallel (4 cores) then I get no errors. If I use parallel I get errors in test 6.
    • I have moved the RAM to different slots in the mobo - the slots appear to be fine and the behavior is the same no matter the slots (1 and 3 vs 2 and 4)
    • Ive pretty much eliminated the possibility that this is anything related to voltages or power. I spent hours playing with voltages to see if it impacted results, CPU SA voltage, IO Voltage, RAM voltage, among others. I also ran CPU at stock speeds during my testing to make sure no cpu issues were causing the problem.
    • At 3000mhz 14-14-14-34 with both sticks in and in dual channel I am 100% rock stable in testing. If I bump to 3200mhz with 16-16-16-36 I am seeing errors. If I loosen timings even further, even up to 19 cas, I still see errors at 3200mhz with both sticks installed. There is just no scaling at all here - its like im hitting a ceiling with the motherboard and it simply cant talk to the two sticks in dual channel without errors beyond a certain speed - and the timings make no difference.
    • I tried some older bios releases on the board to see if it made a difference but the behavior was 100% the same. Literally NOTHING I do with voltage or timings will let the ram run without errors at 3200mhz and beyond in dual channel. Drop to single channel 1 stick and the RAM starts to behave like I would expect B-die to behave.

    After my hours and hours of pouring over this issue, I have been left with conclusion in my mind that this is not an issue of faulty ram modules, even though that was my initial thought when I started seeing errors in memtest86. As I have troubleshot the issue, I have come to the conclusion that the issues I'm seeing come down to an incompatability between the set of G.Skill b-die memory, and the MSI z270A-Pro Motherboard. The fact that 1stick by itself all of a sudden can run at speeds hundreds of mhz higher than 2 sticks together can says a lot to me. Im curious what conclusion others would make given these facts. When I get home tonight and test the new hardware I will be able to know for certain, hopefully, if the RAM is in fact good. The New mobo is listed on the RAM's QVL list, so I have hope I wont encounter the same incompatibility.
     
  2. Easiest way to tell would be to stick them in another system and see what happens.
     
  3. krazymagic

    krazymagic Guest

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    Of course. I do have a 2nd desktop but it has a locked down, generic OEM level bios. As mentioned in my post however, this evening I will be slotting them in a z390 board, so I should have lots of answers after tonight. Im crossing my fingers on the RAM not being bad. If I get errors on the new set up tonight in memtest It will be pretty annoying.
     
  4. krazymagic

    krazymagic Guest

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    God these forums are dead these days. I havent posted here in a long time. I guess to update my thread though real quick in case someome happens across it via search engine some time and finds it helpful: My issue ended up being an incompatability between my Samsung B-die Gskill ripjaws memory and the z270-A Pro motherboard. Once i got the new system together and the latest bios on the mobo - MSI MEG z390 ACE + i7 9700k, I was able to boot and run the ram at XMP, and before I quite for the night I booted for a quick memtest run at 3600mhz 16-16-16-36 and successfully ran 1 full pass. This weekend I plan to really begin the overclock of the new cpu and ram. Im relieved to know it was just an incompatibility. Had I went on initial test results in this case I would have considered the RAM to be bad an likely RMA'd it.
     

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