Upgrading my iMac's memory

[harry20larry]

I have just ugraded my late 2008 unibody Macbook to 4GB of Ram, giving me 2GB DDR3 spare.
Basically my early 2008 iMac has 1GB of DDR2 Ram installed and I have noticed it is a bit sluggish from time to time.
I have seen a guy on youtube use RAM from his iMac and put it into his plastic macbook.
I was wondering if I could do the same with the ram I have from my MacBook, it DDR3 and the iMac is DDR2, however the early 2009 model has DDR3 so does this mean older models that are exactly the same physically-wise can have DDR3.
Thanks,
Harri

 

[Tallest Skil]

DDR2 ≠ DDR3

You can't interchange them.

 

[Shake 'n' Bake]

DDR2 ≠ DDR3

You can't interchange them.

What's the worst that could happen? I'm not sure if this is widely practiced, but I put 256 MB of DDR2 RAM in a digital audio G4.

 

[flopticalcube]

Pin layout and count is different. It won't fit.

 

[Shake 'n' Bake]

Pin layout and count is different. It won't fit.

Too bad.