Why isn't Vram usage tested

[Tr3vor]

2 gb can barely run all the games currently out. I prefer my cards to not be obsolete when i buy them. Watch this video, Linus shows that the GTX 680 2gb and 660ti are held back by memory amount. 

 

*snip*

 

if the 660Ti and 680 are held back by the memory amounts why aren't the FPS dropping below 3 or so? when you run out of VRAM, you get a drop to nearly no FPS, not 5 FPS slower than the 7970 or whatever.