I don't know your budget but look for a 6670, they are about $60 and are infinitely faster than a 610. Cards climb very rapidly in price to performance around the 6670 price range, below that you are paying only a little bit less but are getting a fraction of the performance. 1GB vs 2GB is no difference until the capacity is exceeded, but with light gaming it won't matter too much, and unless you are at 1080p or above theres no difference what so ever.