imac upgrade question

I'm a PC guy but my wife has an iMac, older model.

27" mid-2011
i5-2500S 2.70GHz
8GB
Radeon HD6770M 512MB

I scrapped out a smaller iMac at my day job, and have an i7-2600 3.40GHz and HD6970 to throw in hers. This will already be a substantial upgrade.

This is where my being a PC guy comes into play. I know later Intel motherboards with 2nd gen I-series processors can use 3rd gen processors. Has anyone ever tried this with their Mac? 2nd and 3rd gen are both 1155 socket. Theoretically it should work, but I'm looking for confirmation before I tear it apart twice.

Visit ifixit.com and look at the teardowns for that particular iMac to see how the CPU is held in place, soldered or socketed. If the latter and it's compatible, go for it. If soldered, you're SOL.

It's a removable chip. I've already got the i7-2600 I can replace her i5-2500S with, but would like to move to an i7-3xxx if possible. I posted because I have no idea if Apple has the hardware locked down, or if it's early/late chipsets that will or wont support 2nd AND 3rd gen. Don't really want to waste the time and money on an extra CPU just to find out it's not compatible and have to tear it all down again.

I am pretty sure you can do the swap as long as it's the same socket. If I am wrong sorry. I have for sure read of people with 2009-2011 iMacs with i5 and i7's that have put in a faster CPU.

Maybe have a look here, http://www.xlr8yourmac.com/? Someone there may have tried this.