Putting this shall help the readers too:
In general, for latest titles (eg., BF4, FC3, Crysis3, etc), the graphics quality (settings) usually is:
Tier one cards shall max out with comfortable FPS.
Tier two cards shall be able to play with the following settings with comfortable FPS:
class one: ultra-maxed out
Class two: High-ultra
Class three: High
Tier three cards shall be able to play to play with the following settings with decent FPS:
Class One: High
Class two: Medium-high
Class three: Medium-high, but mostly medium for comfortable FPS
Tier four cards shall be able to play to play with the following settings with decent FPS:
Class one: Medium
Class two: Low-medium
Class three and four: Mostly low but may manage medium
Tier five cards should manage running the games on low settings, may even require lowering the resolution.
NOTES:
All the settings are for FullHD (1080p) resolution, with low to moderate anti-alising settings. High textures preferably.
By comfortable, we here mean 50+ average FPS, decent refers to 40+ average. 60+ is usually excellent and 30+ is usually the least you'd want. Multiplayer is better with more FPS.
Putting anti alising (AA, FXAA, MSAA, etc) on maximum usually takes a heavy toll on FPS/ graphic settings. Texture loading is also subject to VRAM size in some games.
Some latest games may run at higher settings than mentioned, as they vary in coding, base (some are CPU intensive), requirements and may even prefer one arcitecture over another. The above predictment is keeping in mind the most intensive titles, like BF4 and Crysis3.