2009 27" iMac Core i7 can take (2x8GB) 16GB DDR3 1600Mhz RAM?

[Hexley]

While I was googling CMSO16GX3M2A1600C11 for Mac compatibility I came across this really weird post.

http://gathering.tweakers.net/forum/list_message/39364765#39364765

It appears that a 2009 27" iMac Core i7 that should accept (4x4GB) 16GB DDR3 1066MHz RAM can also handle (2x8GB) 16GB DDR3 1600MHz RAM but down clocks it to 1333MHz.

I don't speak German neither am I a member of the forum.

I am just so surprised by this discovery seeming Macs are so picky with RAM.

 

[phoenixsan]

I know....

a little German and seems to me as Dutch....but to the point: Yes, this Mac model can accomodate up to 16 GB of RAM with a speed minimum of 1066 MHz, 204 pins, unbuffered (PC3-8500)

 

[Stingray454]

Yes, it works, but you don't really gain anything from it. I researched this a bit for my 2009 iMac. It has 1066 Mhz memory as standard, but it recognizes memory at 1333 Mhz (or faster) and can use them. The problem is that the memory bus (used to transfer data to/from the memory) is still 1066 Mhz, so you won't gain anything in terms of performance. But yes, it works.

 

[Hexley]

Actually what I found astonishing is that it recognizes 16GB in 2x8GB even if it has 4 memory slots.

I hope it follows for other models as well. I have friends with defective memory slots are discouraged to make out their Macs because of it.

 

[lixuelai]

The late 2009 Nehalem based iMacs can take up to 32GBs of memory so yes it can take 16GB in 2x8GB. The actual speed of the memory typically doesn't matter as long as it is higher since memory modules typically has downclocked settings in the SPD.

 

[Hexley]

The late 2009 Nehalem based iMacs can take up to 32GBs of memory so yes it can take 16GB in 2x8GB. The actual speed of the memory typically doesn't matter as long as it is higher since memory modules typically has downclocked settings in the SPD.

No joke? According to Intel's site the Core i7-860 found on the iMac I mentioned can only do 16GB.

 

[lixuelai]

No joke? According to Intel's site the Core i7-860 found on the iMac I mentioned can only do 16GB.

Intel never tested 8GB sticks as they weren't common when Nehalem was released. The i7 860 does work with 32GBs of RAM (in fact any Nehalem can handle 2x the RAM it is advertised to). Anyway look on this forum plenty of people have tried it with success.

 

[Hexley]

Intel never tested 8GB sticks as they weren't common when Nehalem was released. The i7 860 does work with 32GBs of RAM (in fact any Nehalem can handle 2x the RAM it is advertised to). Anyway look on this forum plenty of people have tried it with success.

I poked around and I am astonished by my discoveries!