yup, the 740G has the same onboard graphics as the 690G which is a generation older. the southbridge is the same as that of the 780G - but that doesnt make a big difference.
the onboard graphics in the 690G/740G is from the old Radeon X1300 series. a bit lesser in performance, called the X1250.
the one in the 780G owes its ancestry to the more recent HD3450, and is called the HD3200
of course , if you are more serious about gaming , get a dedicated gfx card. what sort of games do you play/ did you have a gfx card before ?