L502x memory problems

My L502x twice (at a week or two's interval) BSODed in ntfs.sys, which at first made me suspect a bad HD. But I've done the Dell diagnostics on the HD extensively, nothing.

Next up, bad memory. System shipped from Dell with a 4 gig Samsung and a 2 gig Nanya SODIMM. And this is where it gets interesting. Run memtest86+, it fails on test 5 and 7. Dell memory diags all pass.

I open up the back, try various combinations:
- one SODIMM in (either), no back cover, no problems even after 3+ hours of memtest86+
- both SODIMMs in, no back cover, an error or two in test 7
- both SODIMMs, back cover on, maybe slightly more errors.

I wanted to upgrade to 8G, and a friend is big on having matching RAM, so I buy two new 4G Corsair things. Same problem! (If anything, the two Corsairs, with the back cover on, produced MORE test 7 errors).

The fact that the back cover being closed seems to produce MORE errors is telling me that there's probably a heat-related problem somewhere.

The location of the error seems to change each time, too...

Bad motherboard? Bad thermals? (Bug in memtest86+ 4.20?)

 

So in short, the memory test fails if and only if both slots are used, regardless of which RAMs are being used, is that correct?

I'd try testing each Corsair RAM one by one using memtest86+, to rule out the tiny possibility that you got bad RAMs again. If each passes the test, then it must be a motherboard failure.

 

If and only if both slots are used, and it fails more if the cover thingy is on. That cover business drives me crazy, because it's a PITA to get that thing on/off (though I've gotten far better at it)...

I'm doing another test right now (with Dell's Samsung and one of the Corsairs), so far, no errors, I'm about midway through the troublesome test 7 now.

The sense I'm getting from Googling is that memtest86+ test 7 is more demanding than most other RAM tests?

 

Wow, it just made it through test 7 without errors this time. (with one Corsair, and the Samsung)

Fluke? Or maybe on my 50th attempt, I wedged the SODIMMs into the connectors _just_ right?

Either way, until it BSODs again, I'm not f***ing with it anymore, I think.

 

Well, didn't take long for another BSOD. 0x0000003B this time, no ntfs.sys. Booted back into memtest86+, went right away into test 7. Let's see what it says...

I'm starting to wonder if the A06 BIOS couldn't have something to do with this.

 

More BSODs.

I try again with the two Corsairs. Now it won't even boot Windows.

Putting Dell's mismatched RAM in again. At least I made it to the login screen.

This is getting more and more strange...

 

And right after the login screen, another BSOD.

This thing has seriously taken a turn for the worse.

 

I think it's better for the memory failure to be more prominent. You should call Dell right away and try to get a brand-new replacement unit.

 

A brand new entire laptop?!

 

How long did you have yours? If it's the motherboard failure, I think there's a good case for complete replacement, assuming it's a fairly new unit and that it is a laptop, not a desktop computer.

 

Well, this thing is about 3 months old.

*sigh* Called Dell, I'm going to back it up, then try restoring the factory image. It's being weirder and weirder...

 

Factory image won't cure an obvious hardware issue. I know that was probably Dell tech support telling you that, but they don't know jack. Been there done that with them.

Sounds like a possible bad memory interface on the mobo or a weak memory controller (which is on the CPU in the core-i series).

 

Oh, I know, there's clearly a hardware issue here. But until I can make it fail Dell diagnostics... whoops.

The thing is stable enough that it let me image the drive onto my external HD using Acronis TrueImage (booted off a CD). So, why not go back to the factory image if it amuses them? Ultimately, this is why I have three desktops, three monitors, a netbook, a shiny $99 HP tablet, etc. This thing can be out of commission for a few days, and I'm very annoyed, but not exactly screwed...

 

Oh, and if it is going to be sent to Dell for repair, I might as well be sending them a fresh factory image with no personal information.

 

As predictably obvious, it's BSODing like mad with the factory image too. On phone with Dell now. Three totally different BSODs while I've been talking to this dude...

 

Off to the depot it's headed.

 

It's back. They changed the memory and the system board.

 

Interestingly, this thing had 6GB of RAM when I sent it in, it came back with 8. Odd, no? (in a good way)

(BTW, I restored my backed-up image, and boom, everything is back to the way it was. But the tech had a clean OS with no personal data to work with... so really, I don't mind the little reimage stunt)

 

Well, at least you got something out of it! So no more BSOD?

 

So far so good...