Upgrading RAM for mid 2011 iMac

[weelzSA]

I know the iMac has four RAM slots and can take a max of 16gig RAM, currently I have 4 gig ram (2X 2gig modules) that came stock so basically I want to know do I need to have the same size modules in all four slots or can I add two 4gig RAM modules or just 1 4gig module? I know with normal PC's you can have a mix of different size RAM modules but a little uncertain when it comes to iMac. I hope I am explaining myself correctly? Any help with this would be greatly appreciated.

 

[[)roi(]]

No problem to mix.

 

[weelzSA]

Thanks that's great news. So I could add another 2gig and 4gig module for a total of 10gig RAM if I wanted to? I was just concerened if it had to be in variables of 2's or 4's so thought I'd just double check.

 

[[)roi(]]

Thanks that's great news. So I could add another 2gig and 4gig module for a total of 10gig RAM if I wanted to? I was just concerened if it had to be in variables of 2's or 4's so thought I'd just double check.

Sure that'll work -- just remember to keep the spec the same, otherwise all modules will slow down to the slowest speed -- always best to buy the same spec it came with I.e. 1333 MHz

 

[clasqm]

There are those who say that RAM should be installed in matching pairs:

http://forums.macrumors.com/showthread.php?t=979190

IOW 2x2 GB and 2x4 GB should work but 3x2 and 1x4 would not be optimal. I have no opinion on this myself, just saying what I've read.

 

[[)roi(]]

There are those who say that RAM should be installed in matching pairs:

http://forums.macrumors.com/showthread.php?t=979190

IOW 2x2 GB and 2x4 GB should work but 3x2 and 1x4 would not be optimal. I have no opinion on this myself, just saying what I've read.

The reasoning for this is primarily to match speed on the bus I.e always steps down to the lowest, plus opening an iMac you find its not that visibly apparent which slots are pairs.

 

[clasqm]

The reasoning for this is primarily to match speed on the bus I.e always steps down to the lowest, plus opening an iMac you find its not that visibly apparent which slots are pairs.

Is it unreasonable to suppose that the two slots occupied fresh from the factory are a pair and the two empty ones are another pair?

 

[[)roi(]]

Is it unreasonable to suppose that the two slots occupied fresh from the factory are a pair and the two empty ones are another pair?

Yes that's correct

 

[phiber]

There are those who say that RAM should be installed in matching pairs:

http://forums.macrumors.com/showthread.php?t=979190

IOW 2x2 GB and 2x4 GB should work but 3x2 and 1x4 would not be optimal. I have no opinion on this myself, just saying what I've read.

I've read this too. Read on a site that a macbook with 2x2 gig chips can perform better than one with 1x2gig 1x4gig chip... Not sure how true that is though.