Pcie 2 gpu in pcie 3 slot?

[mucwen]

Im wanting to upgrde to a i5-3570k with z77 mobo but the pcie3 cards seem a little over budget. will a pcie2 card work in the pcie3 slot or should i get a diff mobo and or cpu. i was thinking about getting radeon 6870 or gtx 560. first build so please let me know of other possible issues.
thanks everyone in advance.

 

[Sunius]

Yes it will work.

 

[Deemo13]

Should work fine.

 

[mucwen]

Best answer selected by mucwen.