iMac 27" mid 2010: Can I upgrade the memory to 4x8GB

Yes, the mid-2010 iMac will support 32GB in 4x8GB.

It is also recommended you purchase your RAM from reliable vendors such as Crucial and OWC (www.macsales.com).

I wouldn't recommend OWC, mainly b/c it is overpriced.

You can get 32GB 8x4 of RAM for $150.00.

Corsair 8GB DDR 1333

Model #: CMSA8GX3M1A1333C9

Yes, I have it currently installed.

Well totally incorrect about OWC, very competitive and if you shop you can get 32GB for less than $120. However if you want the best service available it's not free.

$120 for a 32GB DDR3 1333MHz PC3-10600? That's a good find.

I'm not sure what service you would need, but I could tell you NewEgg does not dissappoint.

OWC provides trade in value on your old Ram, telephone support, online chats, live 24hr tech support phone tech support and sales & how to videos. Many of those services are not available from Crucial & NewEgg. For the non tech savy these services could be valuable. By the way it's moo, this thread was answered months ago.

Just saw this thread; I tried to do a similar thing, only purchased just a 16gb upgrade from Patriot (2x8gb). Originally my mid-2010 imac had 4x2gb chips, so I replaced 2 of these with the newer ones. When I plugged machine back in and started it up, it still shows only 8gb with 4 2gb modules. Any thoughts on why this would be? (I have also opened a new thread for this issue, but thought someone on this thread might have an idea).

The new RAM was either not spec'd correctly, was not installed correctly or is defective.

NewEgg does not dissappoint.

Does Newegg offer lifetime warranty on the RAM they sell? They're a good vendor, but I don't believe they offer a warranty on RAM.

As for the price - you get what you pay for. I prefer quality RAM that's been tested and guaranteed to work on a Mac, and lifetime advance replacement warranty.

P.S. Just realized this was an older post I was replying to - did not realize that since there had been new posts today. So, just ignore.

You can even go halfway and reach 24 GB.

I just installed 2 x 8 alongside with my original 2 x 4 and they work perfectly. Interestingly, the iMac will accept PC3-12800 DDR3 @ 1600Mz which was the only memory available at the time of my purchase.

I am trying to upgrade the memory on my 27" iMac mid 2010 model . I currently have 2x2GB, 8x2 (20Gb) in the system and would like to go to 20GB. Is this supported by the chipset in the system ? I am currently running Mac OSX 10.10.2. In my Mac OSX 10.10.2 is showing CPU-i7 860, RAM-12Gb in System Information. What would i do?. Thank you.

Interesting...I am in almost the identical situation and having a very different experience. I manage a lab of twenty mid-2010 iMacs, stocked with the OEM pair of 2GB PC3-10600/1333MHz cards. I wanted to add a pair of 4GB cards to the bank for a total of 12GB each. However, my purchaser acquired the wrong cards....he got twenty PC3-12800/1600MHz and twenty PC3L-12800/1600MHz cards.

I find the following behaviors:

• I cannot have a PC3 and PC3L card in the same machine...we need to add them as matching pairs.
• Even then, I cannot add a matching pair of PC3 or PC3L cards to the original pair of 2GB cards. It's possible I have not yet found the right configuration, though.
• Although the specs say to add the card pairs to the upper two slots, I have to add them to the same side.

So in effect, I am discarding the 2GB cards and adding a pair of 4GB cards on the same side. Am I getting the full 8GB RAM?

Also, can someone tell me exactly which slots correspond to Bank0/DIMM0, Bank0/DIMM1, Bank1/DIMM0 and Bank1/DIMM1?

Thanks

Only if your CPU is Higher than i3 it will support 32gb ram if it is i3 or under then no it will only take 16gb. 2010 iMacs with the i3 processor cannot accept 8GB sticks, but the i5 and i7 can. 4GB sticks is the max it can accept.