resolution means your display resolution and/or the resolution you'll be playing the games at e.g. 1280x1024, 1280x800, 1366x768, 1024x768, 1440x900, 1600x900, 1650x1080, 1920x1080 and so on ......(ran out of breath).
the 6670 1 gb gddr5 will be okay for the first 4-5 resolutions i listed. however to play the games you named, check with their system requirements and the gfx cards they recommended. here's tom's gfx card hierarchy chart, in case you need to compare.http://www.tomshardware.com/reviews/fastest-graphics-card-radeon-geforce,3085-7.html
also make sure your psu can support the gfx card you choose.