iMac 2010 27" logic board fit into a iMac 2009 27"?

Had a dying HDD on my 2009 iMac i7 27”, so I replaced it with a 500GB SSD. upon restart it could only see two of the memory slots (when Apple did a HDD replacement in 2014, I had the up the Ram to 4 - 4GB sticks (16GB total). Long story short I bought new “correct’ ram, no change, no matter which slots I put the sticks in only two are recognized (yes the memory checks out), resets, new OS installs, nothing.

So I was wondering if I can replace the logic board with one from a 2010 27” iMac i7. Can it be done? Logic boards are pretty much the same price.

It is only a tiny bump in “speed” but video, and the whole “package” is faster with turbo?.

Thanks.