Upgrading RAM questions

jabingla2810

macrumors 68020
Original poster
Oct 15, 2008
2,271
937
I have the 27" iMac and it has 4 slots for the RAM.

Currently I have 2x2GB sticks.

Pricing up the RAM, there isn't much difference in price between buying 2x2GB sticks and 2x4GB sticks.

A friend of mine has said that RAM works best when all 4 sticks are of the same value. Is this true?

Reading online I have read that if the RAM sticks are of different values, it is important that the highest value sticks are placed in the right slots. Is this also true?

Apologies for the noob questions.

Thanks
 

GGJstudios

macrumors Westmere
May 16, 2008
44,419
768
A friend of mine has said that RAM works best when all 4 sticks are of the same value. Is this true?
No. There is a slight performance improvement from using matched pairs, but you could have 2 matched pairs that do not match each other.

MR Guide to Matched RAM on Intel Macs
Reading online I have read that if the RAM sticks are of different values, it is important that the highest value sticks are placed in the right slots. Is this also true?
Link to where you read that?
 

btbrossard

macrumors 6502a
Oct 25, 2008
973
11
Chicagoland
I would get the 2x4 GB upgrade to bring your mac to 12 GB total. That seems to going in the $40 range.

Then, in the future if you want more ram, you can buy another 2x4 GB upgrade to bring you to 16 (by replacing the 2 GB sticks).

Ram should be installed in pairs for best performance.

When you put the new ram in your iMac, you can just put the new ram in the free slots.
 

jabingla2810

macrumors 68020
Original poster
Oct 15, 2008
2,271
937
Thanks for the replies

Think ill go for the 2x4GB sticks.

Cheers

*I can't find that website at home, I went to the deep ends of the internet at work.... I'll just ignore I read about it :)
 

MrNomNoms

macrumors 65816
Jan 25, 2011
1,130
249
Wellington, New Zealand
No. There is a slight performance improvement from using matched pairs, but you could have 2 matched pairs that do not match each other.

MR Guide to Matched RAM on Intel Macs

Link to where you read that?
I'd say he is most likely referring to Quad Channel Memory:

http://en.wikipedia.org/wiki/Multi-channel_memory_architecture

Scroll down close to the bottom of the article. IIRC benchmarks I've seen give something like only a 1-3% improvement on average. I've moved 2 x 2GB over to my Mac from my MacBook Pro (same memory as what is installed in my iMac) and I've noticed no performance increase over and above what one would expect from a memory upgrade.
 
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