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System does not POST with some memory sticks

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himmelsee

New Member
Joined
Jun 29, 2022
Motherboard is an old ASUS P8Z77M-PRO, so maybe few will know specific problems. But it is more of generic question:

Is possible that a motherboard (non specific) supports some modules of one model (aka part number) of a memory, but not other modules of the same model (and same manufacturer)?

The problem I have:
I have 2 sets (4 sticks) of CMZ16GX3M2A1600C10. One set works in slots A2 and B2. But the other set does not work in the same slots A2 and B2 (I am trying both sets separatelly first and not together, so only 2 slots are occupied at any time so far). Also none of second set sticks work as a single stick in any slots.

I have also tried 2 identical sets of another manufacturer, another model DDR. Behaviour is the same: MB works perfectly with set one, but does not work at all with set two (DRAM_LED blinks and does not POST).

P.S. the memory is not QVL, BIOS is latest.
P.P.S. Batches are different, manufacturing date differs.
P.P.P.S I tried MEM OK, resetting CMOS, removing CMOS battery and resetting CMOS with no luck. 2 sets out of 4 sets just do not POST...
 
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EarthDog

Gulper Nozzle Co-Owner
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Be sure your BIOS is updated to the latest version. :)

Next, you're installing the two sticks in the wrong slots. Place them in slot A2/B2 (see your manual). Try your kits in the correct slots and see if the behavior changes.

To answer your generic question, yes. The IC's below could be different and the mobo doesn't get along with them.
 
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himmelsee

New Member
Joined
Jun 29, 2022
Be sure your BIOS is updated to the latest version. :)

Next, you're installing the two sticks in the wrong slots. Place them in slot A2/B2 (see your manual). Try your kits in the correct slots and see if the behavior changes.

To answer your generic question, yes. The IC's below could be different and the mobo doesn't get along with them.

I have latest BIOS. Sorry, I provided wrong slot names. Basically I tried A2/B2 (the blue ones).
 

EarthDog

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Tough call.. I mean, your BIOS is updated , but those sticks aren't on the list. They could be bad or just finicky.

You can try manually setting a higher DRAM voltage and timings with the working sticks and trying the others? Otherwise, I'm tapped out and would say sell and get something on the QVL if you need all slots populated.
 

HoraceC

New Member
Joined
May 9, 2022
Hello...

Have you checked the QVL for the CPU? It may shine some light on the issue.
 
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himmelsee

New Member
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Jun 29, 2022
Have you checked the QVL for the CPU? It may shine some light on the issue.
No. I checked only memory QVL (and the RAM I try to use is non QVL). But in any case, what should I look for in QVL for CPU? Asking because the system works with one kit, but not another kit of the same part number memory, and as I understand QVL will just list guaranteed to work part numbers.
 

EarthDog

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You're not looking for anything except your CPU to be on the support/QVL list. :)

Typically, if they aren't on the list, your system wouldn't work with one set and not the other so I doubt that's it.... but still worth looking at to confirm.
 

HoraceC

New Member
Joined
May 9, 2022
Some 2nd Gen Intel processors only support 8GB RAM - this may explain the second module not working.
 

EarthDog

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Some 2nd Gen Intel processors only support 8GB RAM - this may explain the second module not working.
As far as I can read, he's using two kits (4 sticks each) and one set of two sticks from each kit work, the others do not. In other words, two 2x8GB modules are already confirmed to work in the same slots. It's the other two sticks of the two kits that don't. CPU appears to already support 16GB.

EDIT: I also should say that if you bought the same kit (as in a package of four) the IC's should be the same. I *think* I misunderstood in my first post.
 
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himmelsee

New Member
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Jun 29, 2022
As far as I can read, he's using two kits (4 sticks each) and one set of two sticks from each kit work, the others do not. In other words, two 2x8GB modules are already confirmed to work in the same slots. It's the other two sticks of the two kits that don't. CPU appears to already support 16GB.

EDIT: I also should say that if you bought the same kit (as in a package of four) the IC's should be the same. I *think* I misunderstood in my first post.
Not exactly.
I tried two separately bought kits of CMZ16GX3M2A1600C10 (2 sticks per kit). One kit (2 x 8GB) works, another kit (2x8GB) does not. Both kits do not work together (2 x 2 x 8GB) too. Second kit is back to seller, as I bought second kit used (first kit was my old kit). By the way none of the second kit sticks worked standalone too (1 x 8GB)

Then I bought two separate kits of G.Skill F3-2400C11D-16GSR (each kit is 2 x 8GB). Kits have different manufacture dates. One kit works flawlesly (on standard 1333MHz, 1600MHz and even 2400MHz with Intel I7-3770k), another kit does not post at all. Also none of second kit sticks work standalone (1 x 8GB)

So you were right saying that IC's in the kit likely differs. It is just really frustrating when one module with the same part number as another works, but other does not (and I am not trying them together at the moment as I am aware of potential issues of mixing kits).

P.S. I have spoken with manufacturer G.Skill, they so far said that it should work, and saying that likely second kit has both bad modules.
 

EarthDog

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Ok.. gotcha now! The point there was that we already knew the CPU supports 2x8GB. :)

Are you able to RMA the sticks?
 

don256us

Uber Folding Senior
Joined
Jul 17, 2003
So, the first two kits: one you had worked and one you bought did not. I think it's best to look at that fact then set the idea aside. Clearly you were correct to send that kit back to the seller. It did not work even when installed the same as the other kit which did work. Bad kit. It happens and the fact that it was used means that it was more likely to happen than if it was new.

However, now we have two new kits to play with. Same issue? One kit works but the other doesn't? This is less likely to be a memory issue but I'll leave room that it might be as it is used?

Try both sets of working RAM. If the timing is different between kits, install the lower speed into the "Main" slots on the MB.