DDR3 RAM for Late 2009 iMac

[Arthagnan]

It has 1066 MHz DDR3 sticks in it.

Would 1600 MHz DDR3 sticks work too? I assume they will underclock run at 1066 MHz anyway.




http://www.corsair.com/en/memory-by-...m1a1600c9.html

[costabunny]

Originally Posted by Arthagnan

It has 1066 MHz DDR3 sticks in it.

Would 1600 MHz DDR3 sticks work too? I assume they will underclock run at 1066 MHz anyway.

as long as the voltages are within the accepted envelope then there should be no reason that the 1600's would not work (albeit at 1066 as generated by the memory bus).

simply put - yes they should work ok

[Arthagnan]

Originally Posted by costabunny

as long as the voltages are within the accepted envelope then there should be no reason that the 1600's would not work (albeit at 1066 as generated by the memory bus).

simply put - yes they should work ok

Then I will buy 4x4GB and try out. I'll report back later.

[Arthagnan]

I bought 2x4GB (store only had one box left).



I installed them in the upper row and booted my iMac.



BEEP... BEEP... BEEP...

Hm, did not work.

Back with the old modules, and booted fine.

I returned them to the store and got 4x4GB Team 1333 MHz modules.



Same procedure, upper row, two modules to start with. Booted it up again, and BEEP... BEEP... BEEP...


This time I moved them to the lower slots, booted it up again and it WORKED.

Then tried all four. BEEP... BEEP... BEEP... WTF...

Then I tested three modules and one slot empty. BEEP... BEEP... BEEP...

Hmm, after that I mounted one of the old 2GB modules in the empty slot together with three new 4 GB modules, and it worked. So I now got 14 GB of RAM.

No idea really. Two modules works great in the lower slots. But not in the upper.

[Dadioh]

Originally Posted by Arthagnan

It has 1066 MHz DDR3 sticks in it.

Would 1600 MHz DDR3 sticks work too? I assume they will underclock run at 1066 MHz anyway.




http://www.corsair.com/en/memory-by-...m1a1600c9.html

Is it a Core2Duo or the i5/i7 iMac model? On the i5 and i7 the memory controller is built into the CPU so it will auto detect the memory speed and run at that. The Core2Duo machines have the memory controller in the Nvidia MCP chip so not sure if it will try and upclock the memory the same way the i5 and i7 will.

I have two 2009 27" iMacs (one i5 and one i7). They are both happily running 1333MHz memory in all 4 slots.

[Arthagnan]

Originally Posted by Dadioh

Is it a Core2Duo or the i5/i7 iMac model? On the i5 and i7 the memory controller is built into the CPU so it will auto detect the memory speed and run at that. The Core2Duo machines have the memory controller in the Nvidia MCP chip so not sure if it will try and upclock the memory the same way the i5 and i7 will.

I have two 2009 27" iMacs (one i5 and one i7). They are both happily running 1333MHz memory in all 4 slots.

It's a Intel Core 2 Duo (3,06 GHz).

But when I ran 2x4GB in the lower row it reported 1333 MHz.

[Dadioh]

Originally Posted by Arthagnan

It's a Intel Core 2 Duo (3,06 GHz).

But when I ran 2x4GB in the lower row it reported 1333 MHz.

It may be a limitation of the Nvidia MCP then. With my Macbook Pro's with that same Core2Duo/Nvidia combination I know they are finicky with RAM. I stick with PC3-8500 (1066MHz) RAM in those because it is really hit and miss with the 1333MHz RAM unfortunately. I have even had trouble with some PNY PC3-8500 RAM that "should" work but was giving me grief.

If you want the 4 X 4GB combination to work I suggest getting PC3-8500 1066MHz sticks.

[Arthagnan]

Originally Posted by Dadioh

It may be a limitation of the Nvidia MCP then. With my Macbook Pro's with that same Core2Duo/Nvidia combination I know they are finicky with RAM. I stick with PC3-8500 (1066MHz) RAM in those because it is really hit and miss with the 1333MHz RAM unfortunately. I have even had trouble with some PNY PC3-8500 RAM that "should" work but was giving me grief.

If you want the 4 X 4GB combination to work I suggest getting PC3-8500 1066MHz sticks.

Yes, I bet you are right.

I might just run it with 14GB and return one of the 4GB modules.
14GB is plenty, and I think it will run with out hassle. The guy at the store was really nice.
It adds up.

[Dadioh]

Originally Posted by Arthagnan

Yes, I bet you are right.

I might just run it with 14GB and return one of the 4GB modules.
14GB is plenty, and I think it will run with out hassle. The guy at the store was really nice.
It adds up.

Interesting. It sounds to me as if the MCP is getting the RAM timings from that one slot. Probably it looks at all slots and picks the lowest speed and then forces that timing on all the other slots. So what you are achieving is forcing the system to run all the memory at 1066MHz.

If it works it works so you should be happy with the 14GB. Happy iMac'ing

[haddy]

Originally Posted by Dadioh

Is it a Core2Duo or the i5/i7 iMac model? On the i5 and i7 the memory controller is built into the CPU so it will auto detect the memory speed and run at that. The Core2Duo machines have the memory controller in the Nvidia MCP chip so not sure if it will try and upclock the memory the same way the i5 and i7 will.

I have two 2009 27" iMacs (one i5 and one i7). They are both happily running 1333MHz memory in all 4 slots.

Ummm are you saying that you used PC3-10600 DDR3 1333MHz SO-DIMM 204 Pin CL9 SO-DIMM Memory in your Nov 2009 iMac [same as mine]?
Is there a noticeable speed difference?

On a different note this machine was crapping out.....grey screen etc. I finally figured out it was a failing Magic Mouse.....now gone back to wired extended keyboard and wired mouse. Much much better. I will never use a bluetooth input device again

[Dadioh]

Originally Posted by haddy

Ummm are you saying that you used PC3-10600 DDR3 1333MHz SO-DIMM 204 Pin CL9 SO-DIMM Memory in your Nov 2009 iMac [same as mine]?
Is there a noticeable speed difference?

On a different note this machine was crapping out.....grey screen etc. I finally figured out it was a failing Magic Mouse.....now gone back to wired extended keyboard and wired mouse. Much much better. I will never use a bluetooth input device again

Yes. I have 1333MHz modules in both my iMac 27 2009 i7 2.8GHz as well as my wife's iMac 27 2009 i5 2.66GHz. They both run flawlessy. But I didn't get it for speed improvement. It was strictly based on finding a good deal on memory that happened to be that speed. The difference in Geekbench was trivial, maybe 1 or 2%. Any difference I noted was probably due to jumping from 4GB to 16GB.

IMHO, if you have a choice go with the stock 1066MHz stuff for compatibility. If you get a good deal on 1333MHz stuff then you are probably safe but don't expect a big speed improvement.

[haddy]

Originally Posted by Dadioh

Yes. I have 1333MHz modules in both my iMac 27 2009 i7 2.8GHz as well as my wife's iMac 27 2009 i5 2.66GHz. They both run flawlessy. But I didn't get it for speed improvement. It was strictly based on finding a good deal on memory that happened to be that speed. The difference in Geekbench was trivial, maybe 1 or 2%. Any difference I noted was probably due to jumping from 4GB to 16GB.

IMHO, if you have a choice go with the stock 1066MHz stuff for compatibility. If you get a good deal on 1333MHz stuff then you are probably safe but don't expect a big speed improvement.

Hi......thanks for that. Maybe I'll try them though, RAM is just so cheap.

[haddy]

Originally Posted by Dadioh

Yes. I have 1333MHz modules in both my iMac 27 2009 i7 2.8GHz as well as my wife's iMac 27 2009 i5 2.66GHz. They both run flawlessy. But I didn't get it for speed improvement. It was strictly based on finding a good deal on memory that happened to be that speed. The difference in Geekbench was trivial, maybe 1 or 2%. Any difference I noted was probably due to jumping from 4GB to 16GB.

IMHO, if you have a choice go with the stock 1066MHz stuff for compatibility. If you get a good deal on 1333MHz stuff then you are probably safe but don't expect a big speed improvement.

Okay put 16GB of 1333MHz in today .....just going fine......touch wood

[Dadioh]

Originally Posted by haddy

Okay put 16GB of 1333MHz in today .....just going fine......touch wood

Congrats. After installing new memory I usually run a few rounds of Memtest as well as about 10 rounds of CPUTest with "All" option. That should identify if there are any marginality's.

http://osxdaily.com/2011/05/03/memtest-mac-ram-test/

http://cputest.soft32.com

[haddy]

Originally Posted by Dadioh

Congrats. After installing new memory I usually run a few rounds of Memtest as well as about 10 rounds of CPUTest with "All" option. That should identify if there are any marginality's.

http://osxdaily.com/2011/05/03/memtest-mac-ram-test/

http://cputest.soft32.com

Thanks for that..passed both tests ok ok

[Arthagnan]

I replaced the last 2 GB module (1066 MHz ) with a Corsair 4 GB "Apple-memory" (1066) today, but it didn't work. BEEP BEEP BEEP.

[haddy]

Originally Posted by Dadioh

Congrats. After installing new memory I usually run a few rounds of Memtest as well as about 10 rounds of CPUTest with "All" option. That should identify if there are any marginality's.

http://osxdaily.com/2011/05/03/memtest-mac-ram-test/

http://cputest.soft32.com

Hey do you think our machines (late 2009 i7 iMacs) would run (8GBx4), 204-pin SODIMM, DDR3 PC3-10600 memory modules? That is recognise 32GBs of 1333MHz RAM

[Dadioh]

Originally Posted by haddy

Hey do you think our machines (late 2009 i7 iMacs) would run (8GBx4), 204-pin SODIMM, DDR3 PC3-10600 memory modules? That is recognise 32GBs of 1333MHz RAM

The most common response that I have seen is that the 2009 only supports 16GB of RAM. But I did see a post on this forum by a guy who says he has 32GB installed in his iMac 2009 27" i7 machine. I would try it myself but 16GB is already overkill for me. My page outs are always 0.

[Giuly]

You can adjust the memory timing with Thaiphoon Burner, fixing the problem with newer RAM. Here's a video guide for the mid-2010 MacBook Pro, but it's the same procedure on the iMac. If you have bootcamp, you can probably skip the PE thing and just run it from there.
Afterwards, it correctly runs all 4 modules.