Abandoned - Very frustrating RAM problem

[hap2001]

Edit: The laptops in question were sent back, thank you all who tried to help me.

Hi friends, I'm having a RAM related problem that I cannot diagnose by myself.

So I have 2 laptops (A,B) of same model, and 2 sets of RAMs (X,Y) of different model. (Yes 2 sets and 4 sticks total, but to keep the problem not too messy, I always test them within the same set.)

Originally it's A+X and B+Y. Both exhibit random unstable behaviors (A+X more severe), such as crash and lock up, which I later guessed it's RAM related.

I use Memtest86+ to check: A+X errors a lot, B+Y I forgot...
I exchanged them: both A+Y and B+X have no errors.
I exchanged them back: A+X errors less than first time, B+Y no error.

I cleaned both DIMM and socket with ethanol, not fixed.

Since the randomness, I suspect heat related, but then I tested A+Y with vent blocked, so it's hotter than first test, still no error.

One strange thing is, the errors are all across the address range (unlikely to be real bad/weak cells), but stay constant at the same bit within same test, and shift a little across different test/reboot.

Also I don't understand how it can differ with 2 laptops of exact same model and config.

I'm really lost here, can anyone help me?

[Bryn]

I've had problems with RAM sticks before (although that was over 15 years ago) so, as complicated as your issue is (especially when the different RAM sticks had behaved for every test you did with them between the two laptops), I can assume that there might be physical damage in either of them or both or if they're in absolute perfect condition, considering lowering their voltage settings in compliance to both the laptops' BIOS. Also, updating the BIOS in them both would be beneficial if you haven't done so already.

[hap2001]

Thank you!
All 4 sticks are in good physical condition, at least I cannot see any damage with naked eyes.
The laptops cannot set voltage in BIOS.
Both laptop have latest BIOS version.

More info:
Laptops are HP Probook 455 G4 with AMD A9-9410.
They have only single channel IMC.

[nctnico]

Probably the wrong type of memory or cheap garbage. I'd suggest to get quality memory from an A-brand like Kingston. Kingston has a tool on their website to find the right (compatible) memory for your laptops.

[wraper]

If RAM is marginally stable, slight difference in RAM supply voltage or another CPU specimen can make the difference between system being stable or unstable. It probably can be fixed by increasing timings (in bios if it allows it or by modifying SPD).

[eutectique]

but to keep the problem not too messy, I always test them within the same set.

Do you always insert one set the same way? I mean, x1 -> slot 1, x2 -> slot 2. Or did you not care?

When did the problems start? Are these refurbished laptops? 455-G4 was released in 2016. What were they doing in the past 8 years? Compiling Linux kernel 24/7 or being an office browser from 9 to 5? Are you sure the problem is memory and not CPU?

2 slots (supposedly) and 4 sticks give 8 permutations. Try them all, record the result. Repeat for the second laptop.

Or buy yourself new memory of a reputable brand from a reputable seller. Or a new CPU.

[Someone]

If RAM is marginally stable, slight difference in RAM supply voltage or another CPU specimen can make the difference between system being stable or unstable. It probably can be fixed by increasing timings (in bios if it allows it or by modifying SPD).

Even expensive "high end" (S)DRAM could have been sold with narrow electrical margins from new, its a bit of a lottery as to how long ram will last even ECC workstation/server parts.

[Psi]

Probably a timing issue, being a laptop you usually cannot change all the timing and latency settings. So there probably isn't a way to fix it.
The ram likely just isn't compatible with that laptop with the ram timing settings it uses.

Maybe if you pair one stick with another stick that is of a slower speed it may force both to use different timing and then work fine, but meh, probably not worth paying around with.

[thm_w]

Just to check:
- What RAM testing software is being used and how long is it running?

Some RAM errors can take many hours to show up.

[Bryn]

Probably the wrong type of memory or cheap garbage.

You know, I was going to say the exact same thing, but I wasn't sure if that was really the case for him.

Just to check:
- What RAM testing software is being used and how long is it running?

He said he used Memtest86+ to test them in his OP.

[hap2001]

Probably the wrong type of memory or cheap garbage. I'd suggest to get quality memory from an A-brand like Kingston. Kingston has a tool on their website to find the right (compatible) memory for your laptops.

I never use garbage brand parts.

If RAM is marginally stable, slight difference in RAM supply voltage or another CPU specimen can make the difference between system being stable or unstable. It probably can be fixed by increasing timings (in bios if it allows it or by modifying SPD).

Sadly as a typical laptop BIOS, there's no way to change those settings.

Do you always insert one set the same way? I mean, x1 -> slot 1, x2 -> slot 2. Or did you not care?

When did the problems start? Are these refurbished laptops? 455-G4 was released in 2016. What were they doing in the past 8 years? Compiling Linux kernel 24/7 or being an office browser from 9 to 5? Are you sure the problem is memory and not CPU?

Yes I do always insert them the same way.
They are used laptops from ebay, I have the RAM sticks before the laptops and they were working well in Dell machines, I do suspect the laptops instead of the RAM.
However it's strange to have 2 laptops fail the same way.

Just to check:
- What RAM testing software is being used and how long is it running?

Some RAM errors can take many hours to show up.

Memtest86+ v7, 1 pass.

[nctnico]

Yes I do always insert them the same way.
They are used laptops from ebay, I have the RAM sticks before the laptops and they were working well in Dell machines, I do suspect the laptops instead of the RAM.
However it's strange to have 2 laptops fail the same way.

Well, there is your problem: the memory simply isn't compatible with your laptops! Case closed.

If you are lucky, the manufacturer of the memory has a compatibility list.

[eutectique]

Well, there is your problem: the memory simply isn't compatible with your laptops! Case closed.

Or laptops surfaced on ebay because they start to hang up.

[nctnico]

Well, there is your problem: the memory simply isn't compatible with your laptops! Case closed.

Or laptops surfaced on ebay because they start to hang up.

Then it would be a common problem which is easy to discover by using Google to find out if memory problems are common problems for the particular laptop model. Having two laptops with the exact same problem is rare.

[radiolistener]

I had a similar issue with a motherboard based on an Intel chipset and processor. I tried a bunch of different memory sticks from various brands and stores, and all of them failed. The worst failures occurred with different types of Kingston sticks - memtest would show errors almost immediately. Samsung was more stable, but after running memtest for 5-10 hours, it would still show an error. Then I tried overclocking memory from Corsair with passive cooling, and surprisingly, it didn't fail - it successfully passed the tests in memtest for 7 days.

I think the issue might be some kind of incompatibility issue between certain types of memory and the memory controller.

[Bryn]

See... everyone's saying it now. Incompatible memory.

But why were they included in these laptops in the first place, I'll never know... and the one responsible for it should get a slap on the wrist for that.

[wraper]

^Unless RAM is actually faulty, "incompatible" in this case means that laptop does not like this memory. Not that it's incompatible by spec. I once had 2 brand new RAM sticks which simply did not work properly in particular PC. RAM tests were fine but it would BSOD at least once in 1-2 weeks. Even underclocking or leaving just a single stick did not fix the issue. Swapped those with similar sticks in my work PC, and issue got fixed. Work PC had no issue with those either, so I just left it at that.

But why were they included in these laptops in the first place, I'll never know...

Because it worked fine at first glance.
Also most of consumer branded RAM is actually factory overclocked to faster clock, tighter timings than RAM chips are rated for. "Good brands" like Kingston don't hesitate doing it either. It's not just XMP, standard SPD is usually overclocked as well. While this usually works fine, it for sure does not help for compatibility with different hardware.

[Bryn]

But why were they included in these laptops in the first place, I'll never know...

Because it worked fine at first glance.

So let me get this straight... laptops or PCs that happen to have incompatible memory, work absolutely fine the first time? Honestly, that's blown my mind a bit but least that's something new I've learnt so thanks for that...

[wraper]

So let me get this straight... laptops or PCs that happen to have incompatible memory, work absolutely fine the first time?

It's supposed to be compatible. However there are so many possible hardware combinations, manufacturers cannot test all possible pieces of hardware from different manufacturers is they work together with no issues. Often compatibility issues get fixed in bios updates if manufacturer was reported of such.

[eutectique]

But why were they included in these laptops in the first place, I'll never know...

Scroll a bit up to the Reply #10. It says literally:

They are used laptops from ebay, I have the RAM sticks before the laptops and they were working well in Dell machines

[Bryn]

Oh sorry... completely overlooked that. Cheers.

[thm_w]

Just to check:
- What RAM testing software is being used and how long is it running?

Some RAM errors can take many hours to show up.

Memtest86+ v7, 1 pass.

1 pass is not enough to show long term reliability.
I think the minimum recommended is 3, and the "ideal" is 8 passes.

[wraper]

1 pass is not enough to show long term reliability.
I think the minimum recommended is 3, and the "ideal" is 8 passes.

Even if there are no errors after running for 24 hours, it's still not a 100% guarantee that it's actually stable. Just a high chance of it. That's why my main PC has ECC RAM, too much of my nerves wasted on undetectable RAM issues in the past.

[nctnico]

Just to check:
- What RAM testing software is being used and how long is it running?

Some RAM errors can take many hours to show up.

Memtest86+ v7, 1 pass.

1 pass is not enough to show long term reliability.
I think the minimum recommended is 3, and the "ideal" is 8 passes.

I'd let it run for 24 hours or 50 passes or so. If that doesn't turn up a problem, the memory is pretty good. Make sure to enable all tests though if they aren't enabled by default. But if you need to use a PC professionally, buy professional hardware  from HP or Dell. Not the consumer crap.

[magic]

I have seen bit errors which happened within no more than 30~60 minutes of running one particular software on a machine that perfectly passed as many overnight Memtest86 runs as I wanted. I replaced RAM with another type and it all went away.

If it fails Memtest86 it's bad, but Memtest86 doesn't necessarily catch all bad RAM.

I'm using ECC since then. Too much nonsense to worry about.
And fuck Intel, of course.