Because the i5 2320 is the 2nd gen. lga1155 socket cpu, the b85 ( lga1150) doesn't support it, you can buy either b75, H77, Q77, Z75, H67, etc. even H61 can do the job done too. And you don't post what is your budget, and where you will buy the MB, so go to those site find the good deal. http://uk.pcpartpicker.com/parts/partlist/ or http://pcpartpicker.com/ or http://ca.pcpartpicker.com/
Like Gigabyte GA-B75M-D3H, ASRock H77 Pro4-M, etc.