iMac11,3 27", i5 Mid 2010 - 16GB/32GB RAM Logic Board

Yeah,

I have to somewhat agree with you.

Apple is making its computing products in a way that no longer makes them an upgradable, long-term investment.

They are, more and more, designing their stuff as throwaway appliances, now. Making their stuff harder and harder for the end user to upgrade or work on unless you are adventurous and/or skilled enough, have an out of warranty product where one might take a chance and try an work on one of their products, or have a large enough wallet to purchase the current Mac Pro line or even the upcoming newly designed Mac Pro to get that needed user upgradeability and expansion.

Hey Michael,

You said "when i did put in 2 of the old 2GB Rams and fill up the rest with new, it worked fine until i reached that 4GB RAM Limit and it then crashed.". It looks like, yeah, this iMac has a similar problem. I have a question, though - do you think if I add more of the SAMSUNG RAM then I can go over the 4GB limit? The reason I ask is that today I looked at the SAMSUNG RAM that was in my computer (working fine) and the code looks different from other RAM:

PC3-10600S-09-10-F2

I am worndering - if I get more (maybe 2 2GB sticks so I'd be running 8GB of SAMSUNG RAM total), do you think it would work?

I really do not know what is going on with both of your iMacs.

Michael Cologne's replaced Logic board should take the full 16 GBs of RAM.

The 32 GBs of RAM issues aside, Apple states that your model iMac can take up to 16 GBs of RAM.

The Samsung RAM from Apple will work, but you are just spending waaay too much money for it!

I guess because of all of your issues, if you know the Apple Samsung RAM works, I would go for it and go after and purchase/ install as much as you can afford.

You might be able to get by with 8 GBs. If you can install 12 GBs, that will give you a little more RAM as a better buffer against running out of RAM, but this is your call. 4 GB RAM modules are, at least, supposed to work in your model iMac.

There is absolutely no reason why you cannot use 4 GB RAM modules in your iMac model.

I am having an extremely similar problem. I had 2x 4GB DIMMs in my iMac 11,3 i5 that runs rock solid. If I try to upgrade to 8GB DIMMs, the system will boot, but will often report the wrong amount of ram ( 64GB instead of 32GB for instance ) and will only last a random period of time ( 2-5 min ) before kernel panic.

I have tried 3 different batches of RAM from data memory, and just bought and tried OWC... all of them fail in the exact same way.

Even if I run with only 1 x 8GB DIMM it fails. memtest86 crashes immediately. If I go back to my 2x4GB crucial memory, all works again.

I know it's got to be possible to find DIMMs that work.... so many people over the years have said they got theirs working but no one ever posts the exact chips they got working.

😟

Update for everyone who might find this thread and have the same problem. My issue turned out to be that even though I have an i5 processor in my Mid 2010 27 inch iMac, the logic board is the one intended for the i3 ⚠

you can look up your serial number of your iMac on this site:

http://www.thebookyard.com/apple_serial_decode.php

and if it tells you you have an i3, then you have the older logic board.

It's well known the i3's are not upgradable to > 16GB ( more accurately, not more than 4GB DIMMs per slot )

This is why Apple has fixed the "official" limit of these systems to 16GB.

Kind of annoying that I get to find out 5 years later that Apple gave me a motherboard that isn't supposed to go with my CPU.

crhunter, is The Bookyard reliable? I too have a 2010 11,3 i5 iMac with 2x2GB RAM thinking of upgrading. When I enter my iMac's serial number into Bookyard, it wrongly says I have an i7 2.93 processor with maximum RAM of 32GB. What does this mean?

Is 4x4GB apple-samsung original RAM the only modules that work? If so, how exactly so I purchase the original samsung ones from crucial?

Thank you.

Chief Tarun,

I believe this means you have the logic board that will support 32GB of memory. ( I am jealous! )

You definitely don't have to use original Samsung memory, though not all memory vendors will work.

I would only buy from a company like Crucial, DataMemory Systems,or OWC

Both DataMemory and OWC guarantee 4x8GB ( 32GB ) will work in your system.

I know they honor their guarantee because I tried both of them with no less than 4 sets of different memory before I discovered thoe logic board switcheroo that Apple did.

Give it a try! Good luck!

P.S. I do have to admit, that my system, even with the proper memory could only take 12GB and be stable... for some reason if I put in 16GB, it would only last 1-2 days before crashing. ( Sounds strange, but its true... I built PCs for 15 years and never saw such sensitivity to timing, voltages etc as Apple )

Thanks for replying, crhunter.

I'm thinking of ordering first a pair of 8GB DIMMs from OWC. If my iMac is incompatible with such dimms, would it show in the first couple of days or so? Is there a certain number of days without any negative reactions to the RAM after which its safe to stick with the RAM I ordered?

Chief Tarun,

When you get the new memory, shut down the system and take out your old DIMMs. Then put in the two 8GB DIMMs in the first 2 slots ( when the screen is facing you and upright like normal use, these will be the 2 furthest away from you )

Then boot the system. It should boot like normal. If it is going to crash, it will usually do it within the first 5 minutes after booting.

go to "about this Mac" -> more info... -> then click on the memory tab ( I'm using Mavericks, it will be slightly different for other versions )

If the memory is detected as something else other than 8GB, you will definitely have problems. ( Mine detected each module as 24GB when in the 3rd and 4th slot! )

But the best proof is to test the system with the memtest program.

If your motherboard isn't fully compatible with the memory, it will lock up in seconds. ( Hard lockup! )

If this passes the test, then I would shut down the system and add in your old memory into the 2 remaining slots and test again.

Or go and buy 2 more 8GB DIMMs. Try each of those separately....It may not take the memory in that 4th slot.

And run memtest again. If you experience crashes more than say once a week, you might want to experiment with removing one of the DIMMs.
I know that sounds like voodoo, but it was exactly what I needed, and there was nothing wrong with the DIMM itself ( even passed the memtest )

I think it's due to the total power draw on the logic board.

Also, you may want to just dump your original ram. IIRC the memory timings on the original ram were far slower than new chips, so the extra 4GB you get might not be worth it to install them.

Good luck!

John Galt wrote:

Your iMac must have an i5 or i7 CPU to address 32 GB memory.

The i3 CPU cannot use 8 GB DIMMs.

Why? Why cannot i3 address 32GB, but i5 can?