imac (late 09) memory upgrade

Slinxy,

This is strange, I understand that rkaufmann87 has stated that you have the incorrect RAM, but Intel builds the memory controller into the i5/i7 processors and WILL accept 1066 or 1333 memory without issues. You need to be wary of the other specs that aren't supported:

From Apple (http://support.apple.com/kb/HT3912)

DIMMs with any of the following features do not work in the iMac (Late 2009):

Registers or buffers

PLLs

ECC

Parity

EDO RAM

I have 1333 in my 2009 iMac and my 2011 iMac. Works great in all slots.

I do not agree. Specs are specs, if it works some times it does not mean it is OK. Ram especially (downclocking might work without problems, might work often when one slot has the original one, but is never a "good" solution). Remember that higher speed is not making anything faster because it is the bus speed that counts. Read our posts. Never suggest solutions for others that might cause problems, even when it works for you.

I have to 100% agree with Lex on this one. While it may have worked for you first it was a kludge, second you were lucky, and finally it's not consistent with what Apple recommends. To ensure something works follow Apple's recommendations.

The SPECS for the i5/i7 memory controller and the Intel chipset Apple is using specifies that 1066Mhz or 1333Mhz SDRAM DIMMS are compatible.

Quality of RAM or other features may be responsible, but not just the speed of the frontside bus.

The specifications specifically say:

You can find this at http://support.apple.com/kb/SP576

Especially since I was involved in several of the many threads detailing problems with 16 GB third party RAM in late 2009 and up to late 2010 iMacs, it is one thing to consider; however, in this case it seems clear that the main problem should be considered to be the fact that you got the wrong RAM.

Here are the specifications for the late 2009 iMacs from Apple (including the correct RAM):

http://support.apple.com/kb/SP576

And, just in case, here is one of the threads detailing the problems with 16 GB:

https://discussions.apple.com/thread/2567907

Lee, again you are wrong: the same controller is used in different age macs, but it is not meant that you can use these different speeds in the same mac! Even though a mac is laid out with the i5/i7 controller, the total layout can be for for 1333 OR 1066 ram. Not both at the time: as we said it is the bus speed that counts, faster ram will be downclocked to that. It may work, but it may not work also. Period.

I am running 2x4 1333, NOT 1066 in my imac and its been working great for over a year. Apple specs say one thing, but can obviously handle others as well. Both are fine.

I do assume that you saw you were posting in a thread that has been dormant for almost 6 months?

Correct. Some people, like myself, look to these threads for answers at all times. Just providing my experience to help somoene else. Doesnt matter if it was back to 09, an answer is an answer.

Hello all,

I have Imac late 2009 (i7 860) model version 11,1 and as i saw in Wikipedia (to Imac Aluminium table http://en.wikipedia.org/wiki/IMac_%28Intel-based%29#Unibody_iMac) the Logic Board have same FSB rate (2.5GT/s), same MXM slot (i've upgraded HD4850M to HD6970M too) and maybe more ...

A few day's ago, i've decided to try 4 X 4GB Corsair (MAC Edition) 1333 Mhz cas 9 in my Imac to replace 4 x 2GB Hynnix 1066 Mhz, and i was suprised that it perfectly run at 1333 Mhz (saw it in Boostcamp CPU-Z 665 Mhz) and naturaly uder OSX all reconized at speed 1333 Mhz ! (insted of 1066 with olds)

I've played Cysis 2 / FSX along weekend , and no bugs .

Under OSX, no bug too, and more faster for all application.

So to conclude, it works perfecly with this model of Imac (model 11,1) probably not for previous model .

I'm sorry for my pool english.

Oh,

i've foget to give reference of RAM :

2x [CMSA8GX3M2A1333C9 (it is 2x4GB module)] = 16 GB

Best Regards.

I believe that the OP is mistakenly trying to place the DIMMs below rather above the originally installed memory...I had the same issue when I upgraded. I watched this video and was able to see the second slots.

http://www.youtube.com/watch?v=Z4UqhXIcEQ4

I can also confirm that 1333 MHz runs in the late 2009 model (Crucial). Your mileage may vary and I agree you should order 1066 which Apple recommends.

I am posting in old thread as the original question was never answered and I had the same issue.

Regards

scrubbs.me

I have a late 2009 i7 2.8GHz iMac, which originally came with 2 sticks of 2GB Apple RAM running at 1067MHz. I later purchased two more 2GB sticks from OWC, at the same 1067MHz speed. I used my iMac in that condition until last week. June 2013 pricing for RAM had become so cheap I decided to scan the forums to see if the often cheaper 1333MHz RAM would work. Most people who have used it in late 2009 iMacs have reported positive experiences for long term use and even a modest speed bump as well. Since I live in Japan I wanted to ensure that the RAM would be compatible prior to purchase, since international shipping is costly. Thankfully a kind fellow at MacRumors who also lives in Japan directed me to the following RAM on Amazon Japan:

http://tinyurl.com/mnlrvv5

It cost me all of US$100 equivalent, no shipping charges at all.

I too ran GeekBench before and after, and I can attest to the fact that the 1333MHz RAM not only works in late 2009 iMacs, but there is a performance enhancement too that, to me anyway, is more than just numerical -- I can feel it a little bit.

8GB RAM @ 1067MHz

http://browser.primatelabs.com/geekbench2/2020903

16GB RAM @ 1333MHz

http://browser.primatelabs.com/geekbench2/2020945

I installed those two 8GB sticks in the lower two slots (not that such really matters, I don't think). I left the upper two slots free. The reason I did not fill those upper two slots is because (1) 16GB is enough RAM for me, and (2) my previous 2GB sticks were 1067MHz and from what I have read mixing RAM speeds will either slow you to the slowest RAM speed or it will cause problems. To avoid problems I just left the upper two slots open. And hey, it can also be argued that filling only two slots will draw less electric current than filling all four, theoretically meaning less power draw on the iMac's PSU and hence a slightly less amount of heat generated. And even if one argues that slightly more heat is generated with the faster RAM, I would argue that the worse case would be the same amount of heat generated as when I had 4 sticks in there, hence, you have no worries about your iMac overheating at all.

So don't listen to the uninformed nay-sayers. They may be "informed" and "correct" about what's on Apple's official spec sheet, but in terms of the electronics of the late 2009 iMacs and what RAM is truly compatible, you can indeed use 1333MHz RAM. You just need to be sure the other specs of the RAM are compatible (e.g., CL9, no parity, etc.) Since I myself was in doubt about those other specs, I decided to go with RAM that was reported good by another user. And just as that fellow said, the specific RAM I purchased works perfectly.

But don't just take my word for it. Have a look at the experiences of others here:

http://forums.macrumors.com/showthread.php?t=1327771

I hope this helps.