Alternatives: DOTA 2 - HON - Smite - InfiniteCrisis.
Pro tip: switch to dota 2
only on screenshoots, while playing you dont nitice anything diferent.
ingame its not visible.
its not just upgradin your GPU, see your PC as a whole, do you have the PSU to feed the card? do you have a good CPU to avoid bottleneck? etc, etc,.
if you have good fps, forget all this marketing, i have an gtx460 1Gb and still happy with it.
SPOILER: the dog its on your mind and hes the ghost and thats why its called COD: GHOSTS
im thinking in upgrading my pc