Memory upgrade config questions for a 2008 iMac

[slobizman]

I've got an early 2008 iMac with 2GB memory (1+1), and want to upgrade it, as I'm having a few issues running iPhoto and iMovie, plus a few other things, well. My target was 4GB of memory, as 6GB gets a bit expensive for an aging computer.

So, my options are:

(all are PC6400 DDR2 800MHz)

1) Replace memory with 2GB + 2GB (~$60)
2) Replace memory with one 4GB (~$70)
3) Replace one 1GB memory module with a 4GB module, leaving 4GB +1GB. (~$70)

What would be my best choice? In particular, does option #3 have any issues -- would it be better than option #2?

[GGJstudios]

Originally Posted by slobizman

What would be my best choice? In particular, does option #3 have any issues -- would it be better than option #2?

There is a slight performance benefit in using matched pairs of RAM, such as 2x2GB.
MR Guide to Matched RAM on Intel Macs

[slobizman]

Originally Posted by GGJstudios

There is a slight performance benefit in using matched pairs of RAM, such as 2x2GB.
MR Guide to Matched RAM on Intel Macs

Thanks, I understand that.

But that doesn't mean that the 2GB x 2GB config would be better than the single module 4GB config would it?

And if it's not, and I do get the single 4GB module, does adding the 1GB module to the second slot actually slow down the 4GM module?

[GGJstudios]

Originally Posted by slobizman

Thanks, I understand that.

But that doesn't mean that the 2GB x 2GB config would be better than the single module 4GB config would it?

Yes, it would be somewhat better. That's what the article I linked describes.

Originally Posted by slobizman

And if it's not, and I do get the single 4GB module, does adding the 1GB module to the second slot actually slow down the 4GM module?

If the pairs are not matched pairs, it doesn't matter what configuration they are.

[Mike in Kansas]

I have an early 2008 iMac with 6GB. Although I lost the small speed improvement due to dual channel when putting in unmatched sticks, I gained dramatically in reducing page outs. If you don't want to spend the money for the full 6GB, I'd go for the 5GB as I have found that Mountain Lion coupled with iMovie consumes the majority of the RAM, leaving little free for anything else.