Memory configurations in i7 iMac

[CBedo]

Since I need to pull the trigger on a machine soon, and am tired of waiting for a a macbook pro, I'm thinking of buying the 27 inch i7 iMac.

My question relates to memory configuration. If I buy it with the minimum 4 gig, I think that's 2 2 gig modules. Can I buy two third party (OWC or Crucial) 4 gig modules and add them, giving me a total of 12 gig, or would have to get rid of the original 2 2 gig parts? If it's possible to mix the 4 gig pairs with the 2 gigs, will there be any negative performance issues related to that? If I can mix them, do I need to worry about who I buy the 4 gig parts from? Lastly, any positive or negative comments on OWC or Crucial (or other suggestions) for memory in general?

I apologize if that has been discussed before (I'm sure it has). I tried a few searches for the material, but came up empty.

Thanks.

[newuser2310]

you can keep the original 4 gig. The Imac has 4 slots but you have to have matching pairs.

2x 2gig slots 1&2

2x 4gig slots 3&4

I've used crucial before, the memory was sent quickly and it worked.

[Hellhammer]

Yes, you can mix the RAM modules and it will not decrease the performance. Some older Macs' memory controller wasn't able to utilize mismatched RAM but nowadays they do. NewEgg might be little cheaper than OWC or Crucial but you have to know what you're looking for

[CBedo]

Thanks to all for the confirmation. I'm

FYI, here's the prices I found for a pair of 4 gig parts (8 gig total):

Crucial -- 499.99
OWC -- 349.99
Newegg -- 389.99 to 470.99