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ghsDUDE

macrumors 68030
Original poster
May 25, 2010
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I just installed my additional 2x2GB of Ram from OWC last night and when I check "About My Mac" it shows 8GB of RAM (previously there was 4) so I know it was successful.

Today I'm running iTunes and Safari and iTunes starts skipping and this gray Restart screen scrolls down like a curtain. When I restarted my iMac a little yellow triangle notice popped up for a split second and I read the word "Nexus" and when asked to send a report I did. Could the RAM have caused this?
 
I just installed my additional 2x2GB of Ram from OWC last night and when I check "About My Mac" it shows 8GB of RAM (previously there was 4) so I know it was successful.

Today I'm running iTunes and Safari and iTunes starts skipping and this gray Restart screen scrolls down like a curtain. When I restarted my iMac a little yellow triangle notice popped up for a split second and I read the word "Nexus" and when asked to send a report I did. Could the RAM have caused this?
While not impossible, it's unlikely your issue was caused by the RAM.

If you got a screen that looks like this:
TS3742_01_KP-001-en.jpg
It's called a kernel panic. If it doesn't happen again, or very infrequently, don't worry about it.
In most cases, kernel panics are not caused by an issue with your Mac. They are most likely caused by an issue external to your Mac. If the kernel panic doesn't happen again within a few weeks, you don't need to troubleshoot further.
"You need to restart your computer" (kernel panic) message appears (Mac OS X v10.5, 10.6)
Mac OS X 10.7 Help: If “You need to restart your computer” appears
Mac OS X: How to log a kernel panic
Understanding and Debugging Kernel Panics
Resolving Kernel Panics
 
Yes, it could, and it may be the result of mixing two brands of RAM.

Mine was crashing (grey restart/kernel panic type screen at random intervals) after I added two 4GB DIMMS from Crucial (to total 12GB).. Try them in different slots, on mine at least one "bank" is on the left side of the iMac and the other is on the right. You want to match the dimms in each bank and see if that helps.

Weirdly a lot of guides online say the banks are aligned the other way with the two front sockets being one bank and the two rear ones being another. I guess they changed them for different models? Maybe my iMac is just a freak.

edit: It did it 10+ times over a day with the ram in one orientation and hasn't done it once since swapping them out. I was full of dread as it was a new (well, refurb!) iMac and I was getting prepared to send it back!
 
While not impossible, it's unlikely your issue was caused by the RAM.

If you got a screen that looks like this:
TS3742_01_KP-001-en.jpg
It's called a kernel panic. If it doesn't happen again, or very infrequently, don't worry about it.

"You need to restart your computer" (kernel panic) message appears (Mac OS X v10.5, 10.6)
Mac OS X 10.7 Help: If “You need to restart your computer” appears
Mac OS X: How to log a kernel panic
Understanding and Debugging Kernel Panics
Resolving Kernel Panics

That's what is was. I feel like I haven't had one in AT LEAST a month.
But like I said any time I (re)start my iMac a little Yellow Triangle pops up for a split second and I cna't read what it says. Everything else seems to run just fine...would I know if there was a (major) problem with my iMac?

Yes, it could, and it may be the result of mixing two brands of RAM.

Mine was crashing (grey restart/kernel panic type screen at random intervals) after I added two 4GB DIMMS from Crucial (to total 12GB).. Try them in different slots, on mine at least one "bank" is on the left side of the iMac and the other is on the right. You want to match the dimms in each bank and see if that helps.

Weirdly a lot of guides online say the banks are aligned the other way with the two front sockets being one bank and the two rear ones being another. I guess they changed them for different models? Maybe my iMac is just a freak.

edit: It did it 10+ times over a day with the ram in one orientation and hasn't done it once since swapping them out. I was full of dread as it was a new (well, refurb!) iMac and I was getting prepared to send it back!

I put both RAM into the only two empty slots...bottom left and bottom right?
Like the video on OWC shows...I think I did it right?
 
But like I said any time I (re)start my iMac a little Yellow Triangle pops up for a split second and I cna't read what it says. Everything else seems to run just fine...would I know if there was a (major) problem with my iMac?
Yes, you would most likely know if there was a major problem. At what point during the boot up process do you get that triangle warning? Do you have any devices attached when you boot up? If so, try starting without them attached. Also, check Console.app, to see if there are any log messages that might shed some light on what's going on.
 
I put both RAM into the only two empty slots...bottom left and bottom right?
Like the video on OWC shows...I think I did it right?
I think you probably did do it right. That's what I did at first too. That's what Crucial and OWC say but for some reason I get frequent kernel panics in that configuration. When I go into About My Mac now it looks like my attachment, with two 4s in Bank 0 and two 2s in Bank 1. Thats with pairs matched forwards/backwards not left/right, and no kernel panics anymore.

All the dimms passed all the 3rd party memory tests I could get my hands on too.

Maybe someone here has some idea why this could happen. :eek:
 

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I think you probably did do it right. That's what I did at first too. That's what Crucial and OWC say but for some reason I get frequent kernel panics in that configuration. When I go into About My Mac now it looks like my attachment, with two 4s in Bank 0 and two 2s in Bank 1. Thats with pairs matched forwards/backwards not left/right, and no kernel panics anymore.

All the dimms passed all the 3rd party memory tests I could get my hands on too.

Maybe someone here has some idea why this could happen. :eek:

This is what mine looks like...Idk if your theory is right bc it proves Apple doesn't have their Banks set up correctly in the first place?
 

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I think that yellow triangle warning you got might be related to the hard drive. Are you sure it didn't say something about not being able to boot from this disk or partition? I had a problem like this and fixed it with Disk Warrior. Try running the disk utility program and repairing the hard drive.
 
Yes, you would most likely know if there was a major problem. At what point during the boot up process do you get that triangle warning? Do you have any devices attached when you boot up? If so, try starting without them attached. Also, check Console.app, to see if there are any log messages that might shed some light on what's going on.

Should I rearrange my RAM like Mixel is suggesting?
 
Looks like this thread (last 2 post) talk about the same thing.
Personally I think there's nothing to lose by trying, but I can't vouch for it being helpful at all.. I just know it worked for me for reasons I can't explain. :/ I see in that thread (and as far as I can tell - everywhere else) they say the banks are horizontal and it's just System Profiler that's reporting it wrong, but Memtest and Techtool report it the same way. Very weird indeed.
 
Personally I think there's nothing to lose by trying, but I can't vouch for it being helpful at all.. I just know it worked for me for reasons I can't explain. :/ I see in that thread (and as far as I can tell - everywhere else) they say the banks are horizontal and it's just System Profiler that's reporting it wrong, but Memtest and Techtool report it the same way. Very weird indeed.

No more problems here...but do you really think Apple puts them in wrong?
 
It seems very unlikely that Apple would pair the dimms wrongly, so I don't think they do. Whether mine are properly paired now or not, which going by the consensus - they aren't (regardless of what the software is saying).. For some reason horizontally paired Dimms of my variety causes kernel panics on my iMac.

It was crashing every hour or two for a couple of days (i reseated them to check that wasn't it) but not a single crash since vertical pairing. It's very strange, I'm just glad it works. Maybe I should get another matching 8GB set to make sure there isn't some underlying problem with the motherboard or that it can't address all memory at dual channel speed without crashing.
 
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