Have you ever RMA'd RAM modules that didn't work together like this?



  • I've bought a kit of two Kingston DDR4 SO-DIMMs to use in my laptop. They work perfectly, and I'm typing on the laptop with them inside.

    Given that the laptop has 4 RAM slots, I decided to max it out and ordered exact same kit of 2 SO-DIMMs. Everything: voltage, capacity, frequency, vendor, model — everything matched.

    And you know what? The laptop won't start. It won't start with either module present. It will start and let me run pre-boot diagnostics (Dell ePSA) if I first remove the modules, turn it on, let it POST, turn it off, put modules in, and let it POST again. Diagnostics don't report anything fishy even after real thorough tests. But after reboot it won't POST again, blinking "processor failure".

    I'm now going to test them in isolation, but if they turn out to be working, would that even qualify for an RMA?



  • @wft said in Have you ever RMA'd RAM modules that didn't work together like this?:

    I've bought a kit of two Kingston DDR4 SO-DIMMs to use in my laptop. They work perfectly, and I'm typing on the laptop with them inside.

    Given that the laptop has 4 RAM slots, I decided to max it out and ordered exact same kit of 2 SO-DIMMs. Everything: voltage, capacity, frequency, vendor, model — everything matched.

    And you know what? The laptop won't start. It won't start with either module present. It will start and let me run pre-boot diagnostics (Dell ePSA) if I first remove the modules, turn it on, let it POST, turn it off, put modules in, and let it POST again. Diagnostics don't report anything fishy even after real thorough tests. But after reboot it won't POST again, blinking "processor failure".

    I'm now going to test them in isolation, but if they turn out to be working, would that even qualify for an RMA?

    Have you exceeded the maximum capacity of the laptop. For example, one machine I have will support 20GB total, and will support up to 8GB per slot. But you can not use 3 or 4 8GB...



  • @thecpuwizard It supports 64 GB per spec, and 64 (4×16) went in.



  • @wft said in Have you ever RMA'd RAM modules that didn't work together like this?:

    @thecpuwizard It supports 64 GB per spec, and 64 (4×16) went in.

    Well, it was a thought 😉 How is the independent testing going? Post a chart!



  • @wft I'm guessing one of the two new ones is flat-out defective. You could either RMA the whole order, or just the defective one (after your testing).



  • @wft

    The new modules, have you tried just them by themselves (remove the other two)?



  • I also found (the hard way) that it makes a difference for this laptop which slot is first. My current working modules are in slots C and D (because they are under the keyboard, and damn it's hard to remove one), but apparently low addresses where UEFI is mapped are mapped to modules which are in A and B. So if the RAM is defective, there's no chance in hell that the new Dell's technology called "Reliable Memory Technology" (akin to sector remapping/marking in disks) even has a chance to work, or that memtest will even start.



  • Well, with a fail to post you have a number of things you can check:

    Voltage values: You have doubled the ram, you might need to adjust the voltage to handle them.
    Bad dimms: you noted earlier that you have dims A-D with C/D being used for the good ram. Can you still boot if you move the ram from C/D to A/B?
    Bad ram: Try and boot with the "bad" ram in slots C/D and see if it will.

    Mismatched pairs: Some motherboards match A/C and B/D for matched pairs. I have never had an issue placing them wherever, but it may cause problems.



  • @dragoon single stick from „bad” set in slot A works. Of course, it’s not over until all tests pass at least four times. But I can boot it to memtest86, and that’s something.

    I’ll try mixing and matching, but my prediction is that any two sticks in any two slots will work just fine, and adding even one more will make the whole thing not POST.

    If that’s the case, can the RAM controller be to blame?



  • @wft said in Have you ever RMA'd RAM modules that didn't work together like this?:

    If that’s the case, can the RAM controller be to blame?

    You may need to adjust the ram settings within the BIOS. Voltage is a primary one.



  • @dragoon It’s a laptop. Laptop’s ain’t got settings like this, at least you cannot tweak them so readily.

    Just found out that sticks from either set will work in any slot, but if I start mixing them together, I get problems.

    Even if only two sticks, but each from different set.

    Got a BIOS update, will see if it makes a difference.



  • Holy shit, looks like a BIOS damn update worked after all

    Mixed RAM sticks booted. Hammering them with memtest86 now.



  • @wft

    Well that is great news.



  • @dragoon well, until I pop all four of them...

    But dammit, firmware developers look like trwtf lately.



  • @wft
    Well that sucks, if you can't adjust the ram settings in the BIOS than you might see about returning them (it is unlikely that an RMA will help the problem).

    Is the ram that you bought on the approved ram list for the machine? If so you might be able to get help from the manufacturer, if not they will just laugh at you.

    @wft said in Have you ever RMA'd RAM modules that didn't work together like this?:

    But dammit, firmware developers look like trwtf lately.

    always.



  • Nah, got CPU failure after reboot.

    Two stick from one kit = works. Mixing sticks = failure.
    Guess I’ll be replacing them until either it works or they return me the money.



  • Well, the problem kinda solved itself.

    Got only the sticks from the new set in, ran Memtest86 on them, and hallelujah, it started reporting faulty bits! At least I've got a proof why I want to return them.

    (If you're buying stuff as a company, some of the general consumer rules don't apply to you where I live, so I needed to prove the items were indeed faulty.)



  • @wft said in Have you ever RMA'd RAM modules that didn't work together like this?:

    Well, the problem kinda solved itself.

    Got only the sticks from the new set in, ran Memtest86 on them, and hallelujah, it started reporting faulty bits! At least I've got a proof why I want to return them.

    (If you're buying stuff as a company, some of the general consumer rules don't apply to you where I live, so I needed to prove the items were indeed faulty.)

    I only have annecdata but, for my company and personally, I only buy Crucial and have had no more faulty sticks since making that a requirement.

    I've had DOA modules from Corsair and Kingston at work. At home I had a nightmare with some G.Skill sticks that failed Memtest, then the replacements failed Memtest and then I demanded my money back.

    I think Crucial is the only manufacturer that has their own fab as well (they're Micron Semiconductor). Everyone else is a fab-less manufacturer and just buys their chips from Micron, Samsung and the few smaller players.



  • @cursorkeys It's just that I cannot lay my hands on a 64 GB kit from Crucial anywhere in my country.


  • Discourse touched me in a no-no place

    @wft said in Have you ever RMA'd RAM modules that didn't work together like this?:

    And you know what? The laptop won't start. It won't start with either module present. It will start and let me run pre-boot diagnostics (Dell ePSA) if I first remove the modules, turn it on, let it POST, turn it off, put modules in, and let it POST again. Diagnostics don't report anything fishy even after real thorough tests. But after reboot it won't POST again, blinking "processor failure".

    I've had this behaviour before. I had to try putting the RAM in the 4 slots in different combinations, and it only worked when I hit a specific combination (IIRC I think the matched pairs had to be in different channels, but in adjacent slots).

    After Googling the problem, it appeared to be expected behaviour (this was a long time ago, so I can't give you specifics).



  • Well, I’ve got money back for the defective RAM all right. And bought another Kingston kit off another shop.

    And you know what? The new modules also don’t work!

    Bloody technologies! My Thinkpad W530 has 4 modules of RAM from two different vendors and they work just fucking ok.



  • Just had a talk with Kingston support in UK.

    If anything, they have damn good support that actually has a clue. Asking the right questions and actually believing I'm having trouble with their stuff.

    Turned out, Kingston RAM is sensitive to the chipset revision (RAM chipset revision, not the mobo's), and different revisions are almost guaranteed to be incompatible with one another. They went through their stock to find a matching kit to one of the two I have, and will exchange the incompatible one — I only pay for postage.

    It takes a bloody month to upgrade your bloody RAM.


  • Impossible Mission Players - A

    @wft
    Yeah, that's why I stick with Kingston or Corsair memory and pay the premium for them. Their support departments have good, proven track records and put the leg work in to ensure you get what you're paying for.

    Disclaimer: Not to say G.Skill or a Chinesium company aren't producing good RAM or supporting it. But that Kingston and Corsair definitely have a very reliable record of standing with their consumers to make sure their product works. Probably why those two brands are atop Intel's recommended server parts lists.


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