Radeon graphics is the brand name for ATI/AMDs graphics cards. i3, i5 and i7 are Intel processors, but have graphics integrated into them. Any dedicated graphics card (Geforce by Nvidia or Radeon by AMD) will destroy graphics performance straight from a processor. Provided you don't buy a $30 card thats 4 years old.
you will also find "Radeon" graphics integrated in motherboards and laptops as well... with a laptop, it's about as good as youre gonna get... with a desktop computer, not so good when it's "integrated" into the motherboard.