I've ordered a new Zoostorm i3 computer and am considering buying a Radeon HD 6770 1GB, too. I've looked around the internet but haven't found much out about the motherboard and power supply. Does anybody know if the two are compatible?
Most video cards are compatible with modern motherboards, as long as your power supply can provide enough power to power the whole thing.
Since you've got an i3 2120 in that computer, the motherboard is definitely compatible because all intel chip-sets for 2nd generation sandy bridge CPUs are compatible with the HD 6770 series. the 6770 also doesn't draw that much power, so I think you should be fine.
All things considered though, the integrated graphics on the i3 is better than you think, you may not see a big difference putting in a 6770. may I recommend an HD 7770 or at least 7750?
FYI, for games, find the relevant resolution for you, and look at fps. generally fps higher than 30 is considered playable, and at the end of the day, unless you want to brag to your friends about that GPU in your computer, everyone just wants to spend the least amount possible and still play all the games they love