[WizOSX]

This is not an option that Apple offers but others here have said it should work. Any speed hit due to the unmatched pair that anyone can see? I'd like to try this.

[dbranham]

I've got 1.5gb in my iMac CoreDuo (not Core2Duo), and it's a huge boon when compared to the 512gb. That's probably obvious. But, I researched this issue extensively before choosing to upgrade to that particular denomination. My conclusion was that matched ram isn't all it's cracked up to be. Everyone seemed to think there would only be a very slight performance jump by virtue of the matched pair. At least one pundit opined that users will see better performance from 1.25gb in an unmatched pair than they would see with 1gb in a matched pair.

I presume the same applies to the C2D.

[freediverdude]

I don't see how there would not be some performance jump going from 1 gb to 1.5 gb. From what I've read in other threads (I think maybe over at macrumors but I'm not sure), the extra performance you get from the matched pair is fairly small, like less than 10%. I have a core2duo also, and that's what I'm planning to do, is replace one 512 with a 1gb real soon to make 1.5, and then maybe next year buy another 1 gb stick to replace the other 512. That way I don't have to pay for the whole 2gb kit at once.

[WizOSX]

freediverdud--

My thoughts exactly but--you hate to try something no one else has tried.

[WizOSX]

Anyone else tried it??

[badsey]

iMac core dual 1.5 GB

I went with Crucial memory (Apple OEM - at that time).

Goto NewEgg.com and look at their feedback on what is cheap and working for Macs. Crucial also has a system look-up so you buy the correct memory (write down the memory stats and then use it to find cheaper brands).

[Mongoos150]

Ack this has been asked a hundred times. Paired ram does NOT make a difference in these systems. Older systems took advantage of identicle ram architecture in RAM sticks. Not so now.

[iMacYouMac]

You are wrong. Matched pairs DO make a different. The architecture is dual channel, therefore, by using identical matching pairs gives you the double memory bandwidth (dual channel). Not having matching pairs gives you single channel performance. But, 1.5gb single channel is more beneficial than 512 dual channel for obvious reasons.

[Mongoos150]

You are incorrect. New Intel Core2Duo chips do NOT utilize dual channel architecture - there is NO performance benefit. This issue has been beaten to death. Check PC Mag or others for scientific tests. Your memory bandwidth does not increase twofold when using paired ram on these systems. It did in the PowerPC days. Not anymore.

[mduell]

Originally Posted by Mongoos150 

You are incorrect. New Intel Core2Duo chips do NOT utilize dual channel architecture - there is NO performance benefit. This issue has been beaten to death. Check PC Mag or others for scientific tests. Your memory bandwidth does not increase twofold when using paired ram on these systems. It did in the PowerPC days. Not anymore.

WTF? The chipset in the iMacs (945PM) supports dual channel. Did Apple go out of their way to gimp it in the firmware?

[Eriamjh]

The speed hit is not noticable in normal use... if it exists.