I am looking into buying HD7850 but can anyone tell me the difference between HD7850 and HD7850 overlocked edition?
amd's aib partners often bin better gpus and overclock them before marketing them. those are sold as 'overclocked edition'. those usually carry a slight to substantial overclock over reference design. overclocked editions also tend to have better coolers to keep the overclocked gpus, vram and other components cool. factory overclocked cards perform slightly better than reference cards in applications and use more power.
I would still be able to overlock regular HD7850 right?
yes, you can overclock a reference 7850. make sure you have a good cooler, sturdy psu, good case airflow. it'd be better if you get a board with 3rd party cooler. update to latest drivers as well.
Sorry for a noob question!
PS. which brand do you guys recommend? MSI vs Sapphire vs XFX?
all three make good 7850 boards. go with whichever has better cooler, warranty etc.
the price difference from reference to OC version is marginal at best with the 7850 (like $10), so get the OC version. it will have a better cooler/fans to allow even further OC capability. the reference card may OC the same amount as the OC version, but temps will be lower with the card that has the better cooler.